From 37b8ce79c99f4e8dd1c5aee0d3dd8cfe1ef4249b Mon Sep 17 00:00:00 2001
From: Alan Guo Xiang Tan <gxtan1990@gmail.com>
Date: Mon, 5 Jul 2021 14:17:31 +0800
Subject: [PATCH] FEATURE: Add last visit indication to topic view page.
 (#13471)

This PR also removes grey old unread bubble from the topic badges by
dropping `TopicUser#highest_seen_post_number`.
---
 .../app/components/scrolling-post-stream.js   |  4 +-
 .../app/components/topic-list-item.js         |  4 +-
 .../app/components/topic-post-badges.js       |  7 ++-
 .../discourse/app/controllers/topic.js        |  2 +
 .../app/models/topic-tracking-state.js        | 21 +++----
 .../javascripts/discourse/app/models/topic.js | 35 ++++--------
 .../raw-views/list/post-count-or-badges.js    |  5 +-
 .../discourse/app/routes/topic-from-params.js |  2 +
 .../templates/components/featured-topic.hbs   |  2 +-
 .../components/latest-topic-list-item.hbs     |  2 +-
 .../components/topic-post-badges.hbs          |  7 +--
 .../templates/list/post-count-or-badges.hbr   |  2 +-
 .../app/templates/list/topic-list-item.hbr    |  2 +-
 .../app/templates/topic-post-badges.hbr       |  8 +--
 .../discourse/app/templates/topic.hbs         |  2 +
 .../discourse/app/widgets/post-stream.js      | 28 +++++++---
 .../app/widgets/topic-post-visited-line.js    | 18 ++++++
 .../discourse/tests/acceptance/tags-test.js   |  3 +-
 .../discourse/tests/acceptance/topic-test.js  | 20 +++++++
 .../tests/fixtures/discovery-fixtures.js      |  9 +--
 .../fixtures/private-messages-fixtures.js     |  3 +-
 .../discourse/tests/fixtures/topic.js         | 39 +++++--------
 .../unit/models/topic-tracking-state-test.js  | 15 ++---
 .../stylesheets/common/base/_topic-list.scss  |  2 +-
 .../stylesheets/common/base/topic-post.scss   | 15 +++++
 .../stylesheets/common/components/badges.scss |  3 +-
 .../stylesheets/desktop/category-list.scss    |  4 +-
 .../stylesheets/desktop/topic-post.scss       | 14 +++++
 app/assets/stylesheets/mobile/topic-list.scss |  1 -
 app/assets/stylesheets/mobile/topic-post.scss |  6 ++
 app/assets/stylesheets/wcag.scss              |  1 -
 app/models/post_mover.rb                      | 21 +------
 app/models/post_timing.rb                     |  1 -
 app/models/topic.rb                           |  6 +-
 app/models/topic_user.rb                      | 32 +++++------
 app/serializers/listable_topic_serializer.rb  | 14 ++++-
 app/services/post_alerter.rb                  |  7 ++-
 config/locales/client.en.yml                  | 10 +---
 ...ghest_seen_post_number_from_topic_users.rb | 19 +++++++
 lib/post_creator.rb                           |  1 -
 lib/tasks/import.rake                         |  4 +-
 lib/tasks/posts.rake                          |  1 -
 lib/topics_bulk_action.rb                     |  2 +-
 lib/unread.rb                                 | 26 ++++-----
 plugins/discourse-narrative-bot/plugin.rb     |  2 +-
 .../poll-in-reply-history-test.js.es6         |  6 +-
 .../acceptance/poll-quote-test.js.es6         |  6 +-
 .../acceptance/poll-results-test.js.es6       | 12 ++--
 script/import_scripts/base.rb                 |  4 +-
 script/import_scripts/telligent.rb            |  3 +-
 spec/components/post_destroyer_spec.rb        |  4 --
 spec/components/topics_bulk_action_spec.rb    |  2 -
 spec/components/unread_spec.rb                | 55 +++++++------------
 .../json/sam-s-simple-theme.dcstyle.json      |  2 +-
 spec/models/post_mover_spec.rb                | 33 ++---------
 spec/models/post_timing_spec.rb               | 12 ++--
 spec/models/topic_spec.rb                     |  7 ++-
 spec/models/topic_tracking_state_spec.rb      |  1 -
 spec/models/topic_user_spec.rb                |  3 +-
 spec/requests/api/private_messages_spec.rb    |  6 +-
 spec/requests/api/tags_spec.rb                |  3 +-
 spec/requests/api/topics_spec.rb              | 12 ++--
 spec/requests/topics_controller_spec.rb       |  5 +-
 spec/services/post_alerter_spec.rb            | 10 +++-
 64 files changed, 306 insertions(+), 312 deletions(-)
 create mode 100644 app/assets/javascripts/discourse/app/widgets/topic-post-visited-line.js
 create mode 100644 db/post_migrate/20210624023831_remove_highest_seen_post_number_from_topic_users.rb

diff --git a/app/assets/javascripts/discourse/app/components/scrolling-post-stream.js b/app/assets/javascripts/discourse/app/components/scrolling-post-stream.js
index 612766c807..da490bb0b3 100644
--- a/app/assets/javascripts/discourse/app/components/scrolling-post-stream.js
+++ b/app/assets/javascripts/discourse/app/components/scrolling-post-stream.js
@@ -49,7 +49,9 @@ export default MountWidget.extend({
       "selectedPostsCount",
       "searchService",
       "showReadIndicator",
-      "streamFilters"
+      "streamFilters",
+      "lastReadPostNumber",
+      "highestPostNumber"
     );
   },
 
diff --git a/app/assets/javascripts/discourse/app/components/topic-list-item.js b/app/assets/javascripts/discourse/app/components/topic-list-item.js
index b02993354e..9933e98880 100644
--- a/app/assets/javascripts/discourse/app/components/topic-list-item.js
+++ b/app/assets/javascripts/discourse/app/components/topic-list-item.js
@@ -142,8 +142,8 @@ export default Component.extend({
       classes.push("unseen-topic");
     }
 
-    if (topic.get("displayNewPosts")) {
-      classes.push("new-posts");
+    if (topic.unread_posts) {
+      classes.push("unread-posts");
     }
 
     ["liked", "archived", "bookmarked", "pinned", "closed"].forEach((name) => {
diff --git a/app/assets/javascripts/discourse/app/components/topic-post-badges.js b/app/assets/javascripts/discourse/app/components/topic-post-badges.js
index 78600182a1..aced410bbd 100644
--- a/app/assets/javascripts/discourse/app/components/topic-post-badges.js
+++ b/app/assets/javascripts/discourse/app/components/topic-post-badges.js
@@ -1,13 +1,16 @@
 import Component from "@ember/component";
 import I18n from "I18n";
+import { or } from "@ember/object/computed";
 
 export default Component.extend({
   tagName: "span",
   classNameBindings: [":topic-post-badges"],
-  rerenderTriggers: ["url", "unread", "newPosts", "unseen"],
+  rerenderTriggers: ["url", "unread", "newPosts", "unreadPosts", "unseen"],
   newDotText: null,
+
   init() {
     this._super(...arguments);
+
     this.set(
       "newDotText",
       this.currentUser && this.currentUser.trust_level > 0
@@ -15,4 +18,6 @@ export default Component.extend({
         : I18n.t("filters.new.lower_title")
     );
   },
+
+  displayUnreadPosts: or("newPosts", "unreadPosts"),
 });
diff --git a/app/assets/javascripts/discourse/app/controllers/topic.js b/app/assets/javascripts/discourse/app/controllers/topic.js
index b86f9e5570..ae881ebfaf 100644
--- a/app/assets/javascripts/discourse/app/controllers/topic.js
+++ b/app/assets/javascripts/discourse/app/controllers/topic.js
@@ -68,6 +68,8 @@ export default Controller.extend(bufferedProperty("model"), {
   filter: null,
   quoteState: null,
   currentPostId: null,
+  userLastReadPostNumber: null,
+  highestPostNumber: null,
 
   init() {
     this._super(...arguments);
diff --git a/app/assets/javascripts/discourse/app/models/topic-tracking-state.js b/app/assets/javascripts/discourse/app/models/topic-tracking-state.js
index a36bc2d878..3fcbe2d9e1 100644
--- a/app/assets/javascripts/discourse/app/models/topic-tracking-state.js
+++ b/app/assets/javascripts/discourse/app/models/topic-tracking-state.js
@@ -352,15 +352,14 @@ const TopicTrackingState = EmberObject.extend({
         isSeen !== state.is_seen
       ) {
         const postsCount = topic.get("posts_count");
-        let newPosts = postsCount - state.highest_post_number,
-          unread = postsCount - state.last_read_post_number;
+        let unread;
 
-        if (newPosts < 0) {
-          newPosts = 0;
-        }
-        if (!state.last_read_post_number) {
+        if (state.last_read_post_number) {
+          unread = postsCount - state.last_read_post_number;
+        } else {
           unread = 0;
         }
+
         if (unread < 0) {
           unread = 0;
         }
@@ -368,8 +367,7 @@ const TopicTrackingState = EmberObject.extend({
         topic.setProperties({
           highest_post_number: state.highest_post_number,
           last_read_post_number: state.last_read_post_number,
-          new_posts: newPosts,
-          unread: unread,
+          unread_posts: unread,
           is_seen: state.is_seen,
           unseen: !state.last_read_post_number && isUnseen(state),
         });
@@ -654,14 +652,13 @@ const TopicTrackingState = EmberObject.extend({
     newState.topic_id = topic.id;
     newState.notification_level = topic.notification_level;
 
-    // see ListableTopicSerializer for unread/unseen/new_posts and other
+    // see ListableTopicSerializer for unread_posts/unseen and other
     // topic property logic
     if (topic.unseen) {
       newState.last_read_post_number = null;
-    } else if (topic.unread || topic.new_posts) {
+    } else if (topic.unread_posts) {
       newState.last_read_post_number =
-        topic.highest_post_number -
-        ((topic.unread || 0) + (topic.new_posts || 0));
+        topic.highest_post_number - (topic.unread_posts || 0);
     } else {
       // remove the topic if it is no longer unread/new (it has been seen)
       // and if there are too many topics in memory
diff --git a/app/assets/javascripts/discourse/app/models/topic.js b/app/assets/javascripts/discourse/app/models/topic.js
index 0720289df8..a603aeec26 100644
--- a/app/assets/javascripts/discourse/app/models/topic.js
+++ b/app/assets/javascripts/discourse/app/models/topic.js
@@ -7,7 +7,6 @@ import I18n from "I18n";
 import PreloadStore from "discourse/lib/preload-store";
 import { Promise } from "rsvp";
 import RestModel from "discourse/models/rest";
-import Session from "discourse/models/session";
 import Site from "discourse/models/site";
 import User from "discourse/models/user";
 import { ajax } from "discourse/lib/ajax";
@@ -21,6 +20,7 @@ import { longDate } from "discourse/lib/formatter";
 import { popupAjaxError } from "discourse/lib/ajax-error";
 import { resolveShareUrl } from "discourse/helpers/share-url";
 import DiscourseURL, { userPath } from "discourse/lib/url";
+import deprecated from "discourse-common/lib/deprecated";
 
 export function loadTopicView(topic, args) {
   const data = deepMerge({}, args);
@@ -239,10 +239,16 @@ const Topic = RestModel.extend({
     return url;
   },
 
-  @discourseComputed("new_posts", "unread")
-  totalUnread(newPosts, unread) {
-    const count = (unread || 0) + (newPosts || 0);
-    return count > 0 ? count : null;
+  @discourseComputed("unread_posts", "new_posts")
+  totalUnread(unreadPosts, newPosts) {
+    deprecated("The totalUnread property of the topic model is deprecated");
+    return unreadPosts || newPosts;
+  },
+
+  @discourseComputed("unread_posts", "new_posts")
+  displayNewPosts(unreadPosts, newPosts) {
+    deprecated("The displayNewPosts property of the topic model is deprecated");
+    return unreadPosts || newPosts;
   },
 
   @discourseComputed("last_read_post_number", "url")
@@ -284,25 +290,6 @@ const Topic = RestModel.extend({
     return userPath(username);
   },
 
-  // The amount of new posts to display. It might be different than what the server
-  // tells us if we are still asynchronously flushing our "recently read" data.
-  // So take what the browser has seen into consideration.
-  @discourseComputed("new_posts", "id")
-  displayNewPosts(newPosts, id) {
-    const highestSeen = Session.currentProp("highestSeenByTopic")[id];
-    if (highestSeen) {
-      const delta = highestSeen - this.last_read_post_number;
-      if (delta > 0) {
-        let result = newPosts - delta;
-        if (result < 0) {
-          result = 0;
-        }
-        return result;
-      }
-    }
-    return newPosts;
-  },
-
   @discourseComputed("views")
   viewsHeat(v) {
     if (v >= this.siteSettings.topic_views_heat_high) {
diff --git a/app/assets/javascripts/discourse/app/raw-views/list/post-count-or-badges.js b/app/assets/javascripts/discourse/app/raw-views/list/post-count-or-badges.js
index 5a9573090b..9b1283377b 100644
--- a/app/assets/javascripts/discourse/app/raw-views/list/post-count-or-badges.js
+++ b/app/assets/javascripts/discourse/app/raw-views/list/post-count-or-badges.js
@@ -1,11 +1,10 @@
-import { and, or } from "@ember/object/computed";
+import { and } from "@ember/object/computed";
 import EmberObject from "@ember/object";
 import I18n from "I18n";
 import discourseComputed from "discourse-common/utils/decorators";
 
 export default EmberObject.extend({
-  postCountsPresent: or("topic.unread", "topic.displayNewPosts"),
-  showBadges: and("postBadgesEnabled", "postCountsPresent"),
+  showBadges: and("postBadgesEnabled", "topic.unread_posts"),
 
   @discourseComputed
   newDotText() {
diff --git a/app/assets/javascripts/discourse/app/routes/topic-from-params.js b/app/assets/javascripts/discourse/app/routes/topic-from-params.js
index 35fd8b40dc..f97c7c882e 100644
--- a/app/assets/javascripts/discourse/app/routes/topic-from-params.js
+++ b/app/assets/javascripts/discourse/app/routes/topic-from-params.js
@@ -69,6 +69,8 @@ export default DiscourseRoute.extend({
       "model.currentPost": closest,
       enteredIndex: topic.postStream.progressIndexOfPost(closestPost),
       enteredAt: Date.now().toString(),
+      userLastReadPostNumber: topic.last_read_post_number,
+      highestPostNumber: topic.highest_post_number,
     });
 
     this.appEvents.trigger("page:topic-loaded", topic);
diff --git a/app/assets/javascripts/discourse/app/templates/components/featured-topic.hbs b/app/assets/javascripts/discourse/app/templates/components/featured-topic.hbs
index c6a04a2d69..39b208a305 100644
--- a/app/assets/javascripts/discourse/app/templates/components/featured-topic.hbs
+++ b/app/assets/javascripts/discourse/app/templates/components/featured-topic.hbs
@@ -1,5 +1,5 @@
 {{raw "topic-status" topic=topic}}
 <a href={{topic.lastUnreadUrl}} class="title">{{html-safe topic.fancyTitle}}</a>
-{{topic-post-badges newPosts=topic.totalUnread unseen=topic.unseen url=topic.lastUnreadUrl}}
+{{topic-post-badges unreadPosts=topic.unread_posts unseen=topic.unseen url=topic.lastUnreadUrl}}
 
 <a href={{topic.lastPostUrl}} class="last-posted-at">{{format-age topic.last_posted_at}}</a>
diff --git a/app/assets/javascripts/discourse/app/templates/components/latest-topic-list-item.hbs b/app/assets/javascripts/discourse/app/templates/components/latest-topic-list-item.hbs
index 6d117176b1..d9b8522daf 100644
--- a/app/assets/javascripts/discourse/app/templates/components/latest-topic-list-item.hbs
+++ b/app/assets/javascripts/discourse/app/templates/components/latest-topic-list-item.hbs
@@ -11,7 +11,7 @@
     {{#if topic.featured_link}}
       {{topic-featured-link topic}}
     {{/if}}
-    {{topic-post-badges newPosts=topic.totalUnread unseen=topic.unseen url=topic.lastUnreadUrl}}
+    {{topic-post-badges unreadPosts=topic.unread_posts unseen=topic.unseen url=topic.lastUnreadUrl}}
   </div>
   <div class="bottom-row">
     {{category-link topic.category}}{{discourse-tags topic mode="list"}}{{! intentionally inline to avoid whitespace}}
diff --git a/app/assets/javascripts/discourse/app/templates/components/topic-post-badges.hbs b/app/assets/javascripts/discourse/app/templates/components/topic-post-badges.hbs
index 98e3ea3c3f..9a0f0ff410 100644
--- a/app/assets/javascripts/discourse/app/templates/components/topic-post-badges.hbs
+++ b/app/assets/javascripts/discourse/app/templates/components/topic-post-badges.hbs
@@ -1,8 +1,5 @@
-{{#if unread }}
-  &nbsp;<a href={{url}} title={{i18n "topic.unread_posts" count=unread}} class="badge badge-notification unread">{{unread}}</a>
-{{/if}}
-{{#if newPosts}}
-  &nbsp;<a href={{url}} title={{i18n "topic.total_unread_posts" count=newPosts}} class="badge badge-notification new-posts">{{newPosts}}</a>
+{{#if displayUnreadPosts}}
+  &nbsp;<a href={{url}} title={{i18n "topic.unread_posts" count=displayUnreadPosts}} class="badge badge-notification unread-posts">{{displayUnreadPosts}}</a>
 {{/if}}
 {{#if unseen}}
   &nbsp;<a href={{url}} title={{i18n "topic.new"}} class="badge badge-notification new-topic">{{newDotText}}</a>
diff --git a/app/assets/javascripts/discourse/app/templates/list/post-count-or-badges.hbr b/app/assets/javascripts/discourse/app/templates/list/post-count-or-badges.hbr
index f997dcbff0..4c8a662ca2 100644
--- a/app/assets/javascripts/discourse/app/templates/list/post-count-or-badges.hbr
+++ b/app/assets/javascripts/discourse/app/templates/list/post-count-or-badges.hbr
@@ -1,5 +1,5 @@
 {{#if view.showBadges}}
-  {{raw "topic-post-badges" unread=topic.unread newPosts=topic.displayNewPosts unseen=topic.unseen url=topic.lastUnreadUrl newDotText=newDotText}}
+  {{raw "topic-post-badges" unreadPosts=topic.unread_posts unseen=topic.unseen url=topic.lastUnreadUrl newDotText=newDotText}}
 {{else}}
   {{raw "list/posts-count-column" topic=topic tagName="div"}}
 {{/if}}
diff --git a/app/assets/javascripts/discourse/app/templates/list/topic-list-item.hbr b/app/assets/javascripts/discourse/app/templates/list/topic-list-item.hbr
index e7964e1e32..246606ce35 100644
--- a/app/assets/javascripts/discourse/app/templates/list/topic-list-item.hbr
+++ b/app/assets/javascripts/discourse/app/templates/list/topic-list-item.hbr
@@ -29,7 +29,7 @@
                                    topicId=topic.id
                                    unreadClass=unreadClass~}}
     {{~#if showTopicPostBadges}}
-    {{~raw "topic-post-badges" unread=topic.unread newPosts=topic.displayNewPosts unseen=topic.unseen url=topic.lastUnreadUrl newDotText=newDotText}}
+    {{~raw "topic-post-badges" unreadPosts=topic.unread_posts unseen=topic.unseen url=topic.lastUnreadUrl newDotText=newDotText}}
     {{~/if}}
   </span>
   <div class="link-bottom-line">
diff --git a/app/assets/javascripts/discourse/app/templates/topic-post-badges.hbr b/app/assets/javascripts/discourse/app/templates/topic-post-badges.hbr
index 2580b38a8c..5c1ec0cd2b 100644
--- a/app/assets/javascripts/discourse/app/templates/topic-post-badges.hbr
+++ b/app/assets/javascripts/discourse/app/templates/topic-post-badges.hbr
@@ -1,9 +1,9 @@
 <span class='topic-post-badges'>
-  {{~#if unread ~}}
-    &nbsp;<a href='{{url}}' class='badge badge-notification unread' title='{{i18n "topic.unread_posts" count=unread}}'>{{unread}}</a>
-  {{~/if}}
   {{~#if newPosts ~}}
-    &nbsp;<a href='{{url}}' class='badge badge-notification new-posts' title='{{i18n "topic.total_unread_posts" count=newPosts}}'>{{newPosts}}</a>
+    &nbsp;<a href='{{url}}' class='badge badge-notification unread-posts' title='{{i18n "topic.unread_posts" count=newPosts}}'>{{newPosts}}</a>
+  {{~/if}}
+  {{~#if unreadPosts ~}}
+    &nbsp;<a href='{{url}}' class='badge badge-notification unread-posts' title='{{i18n "topic.unread_posts" count=unreadPosts}}'>{{unreadPosts}}</a>
   {{~/if}}
   {{~#if unseen ~}}
     &nbsp;<a href='{{url}}' class='badge badge-notification new-topic' title='{{i18n "topic.new"}}'>{{newDotText}}</a>
diff --git a/app/assets/javascripts/discourse/app/templates/topic.hbs b/app/assets/javascripts/discourse/app/templates/topic.hbs
index f6fda7edfb..6798b6177a 100644
--- a/app/assets/javascripts/discourse/app/templates/topic.hbs
+++ b/app/assets/javascripts/discourse/app/templates/topic.hbs
@@ -208,6 +208,8 @@
                 gaps=model.postStream.gaps
                 showReadIndicator=model.show_read_indicator
                 streamFilters=model.postStream.streamFilters
+                lastReadPostNumber=userLastReadPostNumber
+                highestPostNumber=highestPostNumber
                 showFlags=(action "showPostFlags")
                 editPost=(action "editPost")
                 showHistory=(route-action "showHistory")
diff --git a/app/assets/javascripts/discourse/app/widgets/post-stream.js b/app/assets/javascripts/discourse/app/widgets/post-stream.js
index b381dc2106..7d2c8afc75 100644
--- a/app/assets/javascripts/discourse/app/widgets/post-stream.js
+++ b/app/assets/javascripts/discourse/app/widgets/post-stream.js
@@ -186,17 +186,19 @@ export default createWidget("post-stream", {
   tagName: "div.post-stream",
 
   html(attrs) {
-    const posts = attrs.posts || [],
-      postArray = posts.toArray(),
-      result = [],
-      before = attrs.gaps && attrs.gaps.before ? attrs.gaps.before : {},
-      after = attrs.gaps && attrs.gaps.after ? attrs.gaps.after : {},
-      mobileView = this.site.mobileView;
+    const posts = attrs.posts || [];
+    const postArray = posts.toArray();
+    const postArrayLength = postArray.length;
+    const maxPostNumber = postArray[postArrayLength - 1].post_number;
+    const result = [];
+    const before = attrs.gaps && attrs.gaps.before ? attrs.gaps.before : {};
+    const after = attrs.gaps && attrs.gaps.after ? attrs.gaps.after : {};
+    const mobileView = this.site.mobileView;
 
     let prevPost;
     let prevDate;
 
-    for (let i = 0; i < postArray.length; i++) {
+    for (let i = 0; i < postArrayLength; i++) {
       const post = postArray[i];
 
       if (post instanceof Placeholder) {
@@ -276,6 +278,18 @@ export default createWidget("post-stream", {
         );
       }
 
+      if (
+        i !== postArrayLength - 1 &&
+        maxPostNumber <= attrs.highestPostNumber &&
+        attrs.lastReadPostNumber === post.post_number
+      ) {
+        result.push(
+          this.attach("topic-post-visited-line", {
+            post_number: post.post_number,
+          })
+        );
+      }
+
       prevPost = post;
     }
 
diff --git a/app/assets/javascripts/discourse/app/widgets/topic-post-visited-line.js b/app/assets/javascripts/discourse/app/widgets/topic-post-visited-line.js
new file mode 100644
index 0000000000..85f8ad9552
--- /dev/null
+++ b/app/assets/javascripts/discourse/app/widgets/topic-post-visited-line.js
@@ -0,0 +1,18 @@
+import I18n from "I18n";
+import { createWidget } from "discourse/widgets/widget";
+import { h } from "virtual-dom";
+
+export default createWidget("topic-post-visited-line", {
+  tagName: "div.topic-post-visited-line",
+
+  buildClasses(attrs) {
+    return [`post-${attrs.post_number}`];
+  },
+
+  html() {
+    return h(
+      "span.topic-post-visited-message",
+      I18n.t("topics.new_messages_marker")
+    );
+  },
+});
diff --git a/app/assets/javascripts/discourse/tests/acceptance/tags-test.js b/app/assets/javascripts/discourse/tests/acceptance/tags-test.js
index 3c259a88bb..02b253cceb 100644
--- a/app/assets/javascripts/discourse/tests/acceptance/tags-test.js
+++ b/app/assets/javascripts/discourse/tests/acceptance/tags-test.js
@@ -53,8 +53,7 @@ acceptance("Tags", function (needs) {
               archetype: "regular",
               unseen: false,
               last_read_post_number: 1,
-              unread: 0,
-              new_posts: 1,
+              unread_posts: 1,
               pinned: false,
               unpinned: null,
               visible: true,
diff --git a/app/assets/javascripts/discourse/tests/acceptance/topic-test.js b/app/assets/javascripts/discourse/tests/acceptance/topic-test.js
index 061bb13851..49654926e8 100644
--- a/app/assets/javascripts/discourse/tests/acceptance/topic-test.js
+++ b/app/assets/javascripts/discourse/tests/acceptance/topic-test.js
@@ -553,3 +553,23 @@ acceptance("Topic pinning/unpinning as a group moderator", function (needs) {
     );
   });
 });
+
+acceptance("Topic last visit line", function (needs) {
+  needs.user({ moderator: false, admin: false, trust_level: 1 });
+
+  test("visit topic", async function (assert) {
+    await visit("/t/-/280");
+
+    assert.ok(
+      exists(".topic-post-visited-line.post-10"),
+      "shows the last visited line on the right post"
+    );
+
+    await visit("/t/-/9");
+
+    assert.ok(
+      !exists(".topic-post-visited-line"),
+      "does not show last visited line if post is the last post"
+    );
+  });
+});
diff --git a/app/assets/javascripts/discourse/tests/fixtures/discovery-fixtures.js b/app/assets/javascripts/discourse/tests/fixtures/discovery-fixtures.js
index 5267a5b2bb..b89bcfca39 100644
--- a/app/assets/javascripts/discourse/tests/fixtures/discovery-fixtures.js
+++ b/app/assets/javascripts/discourse/tests/fixtures/discovery-fixtures.js
@@ -4033,8 +4033,7 @@ export default {
           bumped_at: "2019-11-12T05:19:52.848Z",
           unseen: false,
           last_read_post_number: 1,
-          unread: 0,
-          new_posts: 0,
+          unread_posts: 0,
           pinned: false,
           unpinned: null,
           visible: true,
@@ -4076,8 +4075,7 @@ export default {
           bumped_at: "2019-11-12T05:19:32.516Z",
           unseen: false,
           last_read_post_number: 1,
-          unread: 0,
-          new_posts: 0,
+          unread_posts: 0,
           pinned: false,
           unpinned: null,
           visible: true,
@@ -6398,8 +6396,7 @@ export default {
           archetype: "regular",
           unseen: false,
           last_read_post_number: 5,
-          unread: 0,
-          new_posts: 0,
+          unread_posts: 0,
           pinned: false,
           unpinned: null,
           visible: true,
diff --git a/app/assets/javascripts/discourse/tests/fixtures/private-messages-fixtures.js b/app/assets/javascripts/discourse/tests/fixtures/private-messages-fixtures.js
index e6e22c502a..cbacf8dd9e 100644
--- a/app/assets/javascripts/discourse/tests/fixtures/private-messages-fixtures.js
+++ b/app/assets/javascripts/discourse/tests/fixtures/private-messages-fixtures.js
@@ -38,8 +38,7 @@ export default {
           bumped_at: "2019-07-26T01:29:24.177Z",
           unseen: false,
           last_read_post_number: 2,
-          unread: 0,
-          new_posts: 0,
+          unread_posts: 0,
           pinned: false,
           unpinned: null,
           visible: true,
diff --git a/app/assets/javascripts/discourse/tests/fixtures/topic.js b/app/assets/javascripts/discourse/tests/fixtures/topic.js
index e37e505657..a5f8b7bbe6 100644
--- a/app/assets/javascripts/discourse/tests/fixtures/topic.js
+++ b/app/assets/javascripts/discourse/tests/fixtures/topic.js
@@ -3018,8 +3018,7 @@ export default {
         bumped_at: "2015-04-08T16:05:09.842Z",
         unseen: false,
         last_read_post_number: 3,
-        unread: 0,
-        new_posts: 1,
+        unread_posts: 1,
         pinned: false,
         unpinned: null,
         visible: true,
@@ -3062,8 +3061,7 @@ export default {
         bumped_at: "2015-04-08T15:40:30.037Z",
         unseen: false,
         last_read_post_number: 2,
-        unread: 0,
-        new_posts: 2,
+        unread_posts: 2,
         pinned: false,
         unpinned: null,
         visible: true,
@@ -3143,8 +3141,7 @@ export default {
         bumped_at: "2015-04-07T09:21:21.570Z",
         unseen: false,
         last_read_post_number: 8,
-        unread: 0,
-        new_posts: 0,
+        unread_posts: 0,
         pinned: false,
         unpinned: null,
         visible: true,
@@ -3187,8 +3184,7 @@ export default {
         bumped_at: "2015-02-22T13:46:26.845Z",
         unseen: false,
         last_read_post_number: 65,
-        unread: 0,
-        new_posts: 0,
+        unread_posts: 0,
         pinned: false,
         unpinned: null,
         visible: true,
@@ -3266,8 +3262,7 @@ export default {
         bumped_at: "2015-03-21T00:33:52.243Z",
         unseen: false,
         last_read_post_number: 1,
-        unread: 0,
-        new_posts: 0,
+        unread_posts: 0,
         pinned: false,
         unpinned: null,
         visible: true,
@@ -4087,8 +4082,7 @@ export default {
           bumped_at: "2015-08-13T10:14:34.799Z",
           unseen: false,
           last_read_post_number: 5,
-          unread: 0,
-          new_posts: 0,
+          unread_posts: 0,
           pinned: false,
           unpinned: null,
           visible: true,
@@ -4117,8 +4111,7 @@ export default {
           bumped_at: "2015-08-13T01:58:35.206Z",
           unseen: false,
           last_read_post_number: 3,
-          unread: 0,
-          new_posts: 0,
+          unread_posts: 0,
           pinned: false,
           unpinned: null,
           visible: true,
@@ -4175,8 +4168,7 @@ export default {
         bumped_at: "2015-08-13T10:14:34.799Z",
         unseen: false,
         last_read_post_number: 5,
-        unread: 0,
-        new_posts: 0,
+        unread_posts: 0,
         pinned: false,
         unpinned: null,
         visible: true,
@@ -4413,8 +4405,7 @@ export default {
           bumped_at: "2017-01-27T03:52:02.119Z",
           unseen: false,
           last_read_post_number: 1,
-          unread: 0,
-          new_posts: 0,
+          unread_posts: 0,
           pinned: false,
           unpinned: null,
           visible: true,
@@ -4690,8 +4681,7 @@ export default {
           bumped_at: "2015-08-13T10:14:34.799Z",
           unseen: false,
           last_read_post_number: 5,
-          unread: 0,
-          new_posts: 0,
+          unread_posts: 0,
           pinned: false,
           unpinned: null,
           visible: true,
@@ -4720,8 +4710,7 @@ export default {
           bumped_at: "2015-08-13T01:58:35.206Z",
           unseen: false,
           last_read_post_number: 3,
-          unread: 0,
-          new_posts: 0,
+          unread_posts: 0,
           pinned: false,
           unpinned: null,
           visible: true,
@@ -4982,8 +4971,7 @@ export default {
           bumped_at: "2015-08-13T10:14:34.799Z",
           unseen: false,
           last_read_post_number: 5,
-          unread: 0,
-          new_posts: 0,
+          unread_posts: 0,
           pinned: false,
           unpinned: null,
           visible: true,
@@ -5012,8 +5000,7 @@ export default {
           bumped_at: "2015-08-13T01:58:35.206Z",
           unseen: false,
           last_read_post_number: 3,
-          unread: 0,
-          new_posts: 0,
+          unread_posts: 0,
           pinned: false,
           unpinned: null,
           visible: true,
diff --git a/app/assets/javascripts/discourse/tests/unit/models/topic-tracking-state-test.js b/app/assets/javascripts/discourse/tests/unit/models/topic-tracking-state-test.js
index d8d5935d07..83cf49e702 100644
--- a/app/assets/javascripts/discourse/tests/unit/models/topic-tracking-state-test.js
+++ b/app/assets/javascripts/discourse/tests/unit/models/topic-tracking-state-test.js
@@ -247,8 +247,7 @@ discourseModule("Unit | Model | topic-tracking-state", function (hooks) {
         {
           highest_post_number: null,
           id: 111,
-          unread: 10,
-          new_posts: 10,
+          unread_posts: 10,
         },
       ],
     };
@@ -271,8 +270,7 @@ discourseModule("Unit | Model | topic-tracking-state", function (hooks) {
         Topic.create({
           highest_post_number: null,
           id: 111,
-          unread: 10,
-          new_posts: 10,
+          unread_posts: 10,
           unseen: true,
           prevent_sync: false,
         }),
@@ -303,8 +301,7 @@ discourseModule("Unit | Model | topic-tracking-state", function (hooks) {
           id: 111,
           unseen: false,
           seen: true,
-          unread: 0,
-          new_posts: 0,
+          unread_posts: 0,
           prevent_sync: false,
         }),
       ],
@@ -338,8 +335,7 @@ discourseModule("Unit | Model | topic-tracking-state", function (hooks) {
           id: 111,
           unseen: true,
           seen: false,
-          unread: 0,
-          new_posts: 0,
+          unread_posts: 0,
           highest_post_number: 20,
           category_id: 1,
           tags: ["pending"],
@@ -348,8 +344,7 @@ discourseModule("Unit | Model | topic-tracking-state", function (hooks) {
           id: 222,
           unseen: false,
           seen: true,
-          unread: 3,
-          new_posts: 0,
+          unread_posts: 3,
           highest_post_number: 20,
         }),
       ],
diff --git a/app/assets/stylesheets/common/base/_topic-list.scss b/app/assets/stylesheets/common/base/_topic-list.scss
index 133b1a66a4..671e45bcb9 100644
--- a/app/assets/stylesheets/common/base/_topic-list.scss
+++ b/app/assets/stylesheets/common/base/_topic-list.scss
@@ -396,7 +396,7 @@ div.education {
   border-top: 3px solid var(--primary-low);
   border-bottom: 1px solid var(--primary-low);
 
-  .badge-notification.new-posts {
+  .badge-notification.unread-posts {
     vertical-align: text-bottom;
   }
 }
diff --git a/app/assets/stylesheets/common/base/topic-post.scss b/app/assets/stylesheets/common/base/topic-post.scss
index be57d2dee6..5e23116fc3 100644
--- a/app/assets/stylesheets/common/base/topic-post.scss
+++ b/app/assets/stylesheets/common/base/topic-post.scss
@@ -1030,6 +1030,21 @@ a.mention-group {
   }
 }
 
+.topic-post-visited-line {
+  border-bottom: 1px solid var(--danger-medium);
+  line-height: 0.1em;
+  text-align: center;
+  margin: 1rem 0px;
+
+  .topic-post-visited-message {
+    position: relative; // Chrome needs this, otherwise the line is above the text
+    background-color: var(--secondary);
+    color: var(--danger-medium);
+    font-size: $font-down-1;
+    padding: 0 8px;
+  }
+}
+
 // Select posts
 
 .topic-post {
diff --git a/app/assets/stylesheets/common/components/badges.scss b/app/assets/stylesheets/common/components/badges.scss
index 7b8387111b..72a26175de 100644
--- a/app/assets/stylesheets/common/components/badges.scss
+++ b/app/assets/stylesheets/common/components/badges.scss
@@ -178,9 +178,8 @@
     color: var(--secondary);
   }
 
-  // New posts
+  // Unread posts
 
-  &.new-posts,
   &.unread-posts {
     background-color: var(--tertiary-med-or-tertiary);
     color: var(--secondary);
diff --git a/app/assets/stylesheets/desktop/category-list.scss b/app/assets/stylesheets/desktop/category-list.scss
index 4b20068251..66e11d1626 100644
--- a/app/assets/stylesheets/desktop/category-list.scss
+++ b/app/assets/stylesheets/desktop/category-list.scss
@@ -62,7 +62,7 @@
     .badge-wrapper {
       margin-right: 0.5em;
     }
-    .badge-notification.new-posts {
+    .badge-notification.unread-posts {
       display: block;
       padding: 0;
     }
@@ -87,7 +87,7 @@
     .topic-statuses {
       margin-right: 0.15em;
     }
-    .topic-post-badges .badge.new-posts,
+    .topic-post-badges .badge.unread-posts,
     .title {
       margin-right: 5px;
     }
diff --git a/app/assets/stylesheets/desktop/topic-post.scss b/app/assets/stylesheets/desktop/topic-post.scss
index a6ab990641..0fcaeeae3f 100644
--- a/app/assets/stylesheets/desktop/topic-post.scss
+++ b/app/assets/stylesheets/desktop/topic-post.scss
@@ -577,6 +577,20 @@ blockquote {
   }
 }
 
+.topic-post-visited-line {
+  width: calc(
+    #{$topic-body-width} + #{$topic-avatar-width} +
+      (#{$topic-body-width-padding} * 2)
+  );
+
+  + .topic-post {
+    .topic-avatar,
+    .topic-body {
+      border-top: none;
+    }
+  }
+}
+
 // variables are used to calculate the width of .gap
 .topic-body {
   width: calc(#{$topic-body-width} + (#{$topic-body-width-padding} * 2));
diff --git a/app/assets/stylesheets/mobile/topic-list.scss b/app/assets/stylesheets/mobile/topic-list.scss
index 1b513ceea1..24599574d9 100644
--- a/app/assets/stylesheets/mobile/topic-list.scss
+++ b/app/assets/stylesheets/mobile/topic-list.scss
@@ -156,7 +156,6 @@ ol.category-breadcrumb {
   }
 
   .category-topic-link td.num .badge-notification {
-    &.new-posts,
     &.unread-posts {
       color: var(--secondary);
     }
diff --git a/app/assets/stylesheets/mobile/topic-post.scss b/app/assets/stylesheets/mobile/topic-post.scss
index e4ae8f7f45..3ae4c7f7b7 100644
--- a/app/assets/stylesheets/mobile/topic-post.scss
+++ b/app/assets/stylesheets/mobile/topic-post.scss
@@ -9,6 +9,12 @@
   }
 }
 
+.topic-post-visited-line {
+  + .topic-post article {
+    border-top: none;
+  }
+}
+
 .topic-post article {
   border-top: 1px solid var(--primary-low);
   padding: 15px 0 8px 0;
diff --git a/app/assets/stylesheets/wcag.scss b/app/assets/stylesheets/wcag.scss
index aac73ba06c..a3ee4a328e 100644
--- a/app/assets/stylesheets/wcag.scss
+++ b/app/assets/stylesheets/wcag.scss
@@ -136,7 +136,6 @@ html {
     background: var(--primary-medium);
   }
 
-  .badge-notification.new-posts,
   .badge-notification.unread-posts {
     background: var(--tertiary);
   }
diff --git a/app/models/post_mover.rb b/app/models/post_mover.rb
index c70ffaa3b0..c1710bb78f 100644
--- a/app/models/post_mover.rb
+++ b/app/models/post_mover.rb
@@ -352,7 +352,7 @@ class PostMover
     }
 
     DB.exec(<<~SQL, params)
-      INSERT INTO topic_users(user_id, topic_id, posted, last_read_post_number, highest_seen_post_number,
+      INSERT INTO topic_users(user_id, topic_id, posted, last_read_post_number,
                               last_emailed_post_number, first_visited_at, last_visited_at, notification_level,
                               notifications_changed_at, notifications_reason_id)
       SELECT tu.user_id,
@@ -370,12 +370,6 @@ class PostMover
                WHERE lr.old_topic_id = tu.topic_id
                  AND lr.old_post_number <= tu.last_read_post_number
              )                                           AS last_read_post_number,
-             (
-               SELECT MAX(hs.new_post_number)
-               FROM moved_posts hs
-               WHERE hs.old_topic_id = tu.topic_id
-                 AND hs.old_post_number <= tu.highest_seen_post_number
-             )                                           AS highest_seen_post_number,
              (
                SELECT MAX(le.new_post_number)
                FROM moved_posts le
@@ -392,7 +386,6 @@ class PostMover
       WHERE tu.topic_id = :old_topic_id
         AND GREATEST(
                 tu.last_read_post_number,
-                tu.highest_seen_post_number,
                 tu.last_emailed_post_number
               ) >= (SELECT MIN(old_post_number) FROM moved_posts)
       ON CONFLICT (topic_id, user_id) DO UPDATE
@@ -409,18 +402,6 @@ class PostMover
                                            GREATEST(topic_users.last_read_post_number,
                                                     excluded.last_read_post_number)
                                          ELSE topic_users.last_read_post_number END,
-            highest_seen_post_number = CASE
-                                         WHEN topic_users.highest_seen_post_number = :old_highest_staff_post_number OR (
-                                             :old_highest_post_number < :old_highest_staff_post_number
-                                             AND topic_users.highest_seen_post_number = :old_highest_post_number
-                                             AND NOT EXISTS(SELECT 1
-                                                            FROM users u
-                                                            WHERE u.id = topic_users.user_id
-                                                              AND (admin OR moderator))
-                                           ) THEN
-                                           GREATEST(topic_users.highest_seen_post_number,
-                                                    excluded.highest_seen_post_number)
-                                         ELSE topic_users.highest_seen_post_number END,
             last_emailed_post_number = CASE
                                          WHEN topic_users.last_emailed_post_number = :old_highest_staff_post_number OR (
                                              :old_highest_post_number < :old_highest_staff_post_number
diff --git a/app/models/post_timing.rb b/app/models/post_timing.rb
index 6738687da3..2670f3d020 100644
--- a/app/models/post_timing.rb
+++ b/app/models/post_timing.rb
@@ -71,7 +71,6 @@ class PostTiming < ActiveRecord::Base
       end
 
       TopicUser.where(user_id: user.id, topic_id: topic.id).update_all(
-        highest_seen_post_number: last_read,
         last_read_post_number: last_read
       )
 
diff --git a/app/models/topic.rb b/app/models/topic.rb
index 9ad202b533..9ab9f9252b 100644
--- a/app/models/topic.rb
+++ b/app/models/topic.rb
@@ -810,11 +810,7 @@ class Topic < ActiveRecord::Base
       SET last_read_post_number = CASE
                                   WHEN last_read_post_number > :highest THEN :highest
                                   ELSE last_read_post_number
-                                  END,
-          highest_seen_post_number = CASE
-                            WHEN highest_seen_post_number > :highest THEN :highest
-                            ELSE highest_seen_post_number
-                            END
+                                  END
       WHERE topic_id = :topic_id
     SQL
   end
diff --git a/app/models/topic_user.rb b/app/models/topic_user.rb
index f86d99ffac..35336d42f9 100644
--- a/app/models/topic_user.rb
+++ b/app/models/topic_user.rb
@@ -1,6 +1,10 @@
 # frozen_string_literal: true
 
 class TopicUser < ActiveRecord::Base
+  self.ignored_columns = [
+    :highest_seen_post_number # Remove after 01 Jan 2022
+  ]
+
   belongs_to :user
   belongs_to :topic
 
@@ -114,6 +118,11 @@ class TopicUser < ActiveRecord::Base
     # since there's more likely to be an existing record than not. If the update returns 0 rows affected
     # it then creates the row instead.
     def change(user_id, topic_id, attrs)
+      # For plugin compatibility, remove after 01 Jan 2022
+      if attrs[:highest_seen_post_number]
+        attrs.delete(:highest_seen_post_number)
+      end
+
       # Sometimes people pass objs instead of the ids. We can handle that.
       topic_id = topic_id.id if topic_id.is_a?(::Topic)
       user_id = user_id.id if user_id.is_a?(::User)
@@ -131,6 +140,7 @@ class TopicUser < ActiveRecord::Base
 
         attrs_sql = attrs_array.map { |t| "#{t[0]} = ?" }.join(", ")
         vals = attrs_array.map { |t| t[1] }
+
         rows = TopicUser.where(topic_id: topic_id, user_id: user_id).update_all([attrs_sql, *vals])
 
         if rows == 0
@@ -252,7 +262,6 @@ class TopicUser < ActiveRecord::Base
     UPDATE_TOPIC_USER_SQL = "UPDATE topic_users
                                     SET
                                       last_read_post_number = GREATEST(:post_number, tu.last_read_post_number),
-                                      highest_seen_post_number = t.highest_post_number,
                                       total_msecs_viewed = LEAST(tu.total_msecs_viewed + :msecs,86400000),
                                       notification_level =
                                          case when tu.notifications_reason_id is null and (tu.total_msecs_viewed + :msecs) >
@@ -278,8 +287,8 @@ class TopicUser < ActiveRecord::Base
 
     UPDATE_TOPIC_USER_SQL_STAFF = UPDATE_TOPIC_USER_SQL.gsub("highest_post_number", "highest_staff_post_number")
 
-    INSERT_TOPIC_USER_SQL = "INSERT INTO topic_users (user_id, topic_id, last_read_post_number, highest_seen_post_number, last_visited_at, first_visited_at, notification_level)
-                  SELECT :user_id, :topic_id, :post_number, ft.highest_post_number, :now, :now, :new_status
+    INSERT_TOPIC_USER_SQL = "INSERT INTO topic_users (user_id, topic_id, last_read_post_number, last_visited_at, first_visited_at, notification_level)
+                  SELECT :user_id, :topic_id, :post_number, :now, :now, :new_status
                   FROM topics AS ft
                   JOIN users u on u.id = :user_id
                   WHERE ft.id = :topic_id
@@ -303,11 +312,6 @@ class TopicUser < ActiveRecord::Base
         threshold: SiteSetting.default_other_auto_track_topics_after_msecs
       }
 
-      # In case anyone sees "highest_seen_post_number" and gets confused, like I do.
-      # highest_seen_post_number represents the highest_post_number of the topic when
-      # the user visited it. It may be out of alignment with last_read, meaning
-      # ... user visited the topic but did not read the posts
-      #
       # 86400000 = 1 day
       rows =
         if user.staff?
@@ -424,12 +428,11 @@ class TopicUser < ActiveRecord::Base
     builder.exec(action_type_id: PostActionType.types[action_type])
   end
 
-  # cap number of unread topics at count, bumping up highest_seen / last_read if needed
+  # cap number of unread topics at count, bumping up last_read if needed
   def self.cap_unread!(user_id, count)
     sql = <<SQL
     UPDATE topic_users tu
-    SET last_read_post_number = max_number,
-        highest_seen_post_number = max_number
+    SET last_read_post_number = max_number
     FROM (
       SELECT MAX(post_number) max_number, p.topic_id FROM posts p
       WHERE deleted_at IS NULL
@@ -456,8 +459,7 @@ SQL
     builder = DB.build <<~SQL
       UPDATE topic_users t
         SET
-          last_read_post_number = LEAST(GREATEST(last_read, last_read_post_number), max_post_number),
-          highest_seen_post_number = LEAST(max_post_number,GREATEST(t.highest_seen_post_number, last_read))
+          last_read_post_number = LEAST(GREATEST(last_read, last_read_post_number), max_post_number)
       FROM (
         SELECT topic_id, user_id, MAX(post_number) last_read
         FROM post_timings
@@ -474,8 +476,7 @@ SQL
       X.topic_id = t.topic_id AND
       X.user_id = t.user_id AND
       (
-        last_read_post_number <> LEAST(GREATEST(last_read, last_read_post_number), max_post_number) OR
-        highest_seen_post_number <> LEAST(max_post_number,GREATEST(t.highest_seen_post_number, last_read))
+        last_read_post_number <> LEAST(GREATEST(last_read, last_read_post_number), max_post_number)
       )
     SQL
 
@@ -496,7 +497,6 @@ end
 #  topic_id                 :integer          not null
 #  posted                   :boolean          default(FALSE), not null
 #  last_read_post_number    :integer
-#  highest_seen_post_number :integer
 #  last_visited_at          :datetime
 #  first_visited_at         :datetime
 #  notification_level       :integer          default(1), not null
diff --git a/app/serializers/listable_topic_serializer.rb b/app/serializers/listable_topic_serializer.rb
index 884884bf7d..77a90b29e7 100644
--- a/app/serializers/listable_topic_serializer.rb
+++ b/app/serializers/listable_topic_serializer.rb
@@ -14,6 +14,7 @@ class ListableTopicSerializer < BasicTopicSerializer
              :last_read_post_number,
              :unread,
              :new_posts,
+             :unread_posts,
              :pinned,
              :unpinned,
              :excerpt,
@@ -115,16 +116,25 @@ class ListableTopicSerializer < BasicTopicSerializer
 
   alias :include_last_read_post_number? :has_user_data
 
+  # TODO: For backwards compatibility with themes,
+  #       Remove once Discourse 2.8 is released
   def unread
-    unread_helper.unread_posts
+    0
   end
   alias :include_unread? :has_user_data
 
+  # TODO: For backwards compatibility with themes,
+  #       Remove once Discourse 2.8 is released
   def new_posts
-    unread_helper.new_posts
+    unread_helper.unread_posts
   end
   alias :include_new_posts? :has_user_data
 
+  def unread_posts
+    unread_helper.unread_posts
+  end
+  alias :include_unread_posts? :has_user_data
+
   def include_excerpt?
     pinned || SiteSetting.always_include_topic_excerpts || theme_modifier_helper.serialize_topic_excerpts
   end
diff --git a/app/services/post_alerter.rb b/app/services/post_alerter.rb
index ec7c13f084..90b4516a68 100644
--- a/app/services/post_alerter.rb
+++ b/app/services/post_alerter.rb
@@ -752,7 +752,12 @@ class PostAlerter
 
     DiscourseEvent.trigger(:before_create_notifications_for_users, notify, post)
 
-    already_seen_user_ids = Set.new TopicUser.where(topic_id: post.topic.id).where("highest_seen_post_number >= ?", post.post_number).pluck(:user_id)
+    already_seen_user_ids = Set.new(
+      TopicUser
+        .where(topic_id: post.topic.id)
+        .where("last_read_post_number >= ?", post.post_number)
+        .pluck(:user_id)
+    )
 
     each_user_in_batches(notify) do |user|
       notification_type = !new_record && already_seen_user_ids.include?(user.id) ? Notification.types[:edited] : Notification.types[:posted]
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index 9c28505b31..ac33686a38 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -2397,7 +2397,7 @@ en:
         top: "There are no top topics."
         educate:
           new: '<p>Your new topics will appear here. By default, topics are considered new and will show a <span class="badge new-topic badge-notification" style="vertical-align:middle;line-height:inherit;"></span> indicator if they were created in the last 2 days.</p><p>Visit your <a href="%{userPrefsUrl}">preferences</a> to change this.</p>'
-          unread: '<p>Your unread topics appear here.</p><p>By default, topics are considered unread and will show unread counts <span class="badge new-posts badge-notification">1</span> if you:</p><ul><li>Created the topic</li><li>Replied to the topic</li><li>Read the topic for more than 4 minutes</li></ul><p>Or if you have explicitly set the topic to Tracked or Watched via the 🔔 in each topic.</p><p>Visit your <a href="%{userPrefsUrl}">preferences</a> to change this.</p>'
+          unread: '<p>Your unread topics appear here.</p><p>By default, topics are considered unread and will show unread counts <span class="badge unread-posts badge-notification">1</span> if you:</p><ul><li>Created the topic</li><li>Replied to the topic</li><li>Read the topic for more than 4 minutes</li></ul><p>Or if you have explicitly set the topic to Tracked or Watched via the 🔔 in each topic.</p><p>Visit your <a href="%{userPrefsUrl}">preferences</a> to change this.</p>'
       bottom:
         latest: "There are no more latest topics."
         posted: "There are no more posted topics."
@@ -2457,15 +2457,9 @@ en:
       not_found:
         title: "Topic not found"
         description: "Sorry, we couldn't find that topic. Perhaps it was removed by a moderator?"
-      total_unread_posts:
+      unread_posts:
         one: "you have %{count} unread post in this topic"
         other: "you have %{count} unread posts in this topic"
-      unread_posts:
-        one: "you have %{count} unread old post in this topic"
-        other: "you have %{count} unread old posts in this topic"
-      new_posts:
-        one: "there is %{count} new post in this topic since you last read it"
-        other: "there are %{count} new posts in this topic since you last read it"
       likes:
         one: "there is %{count} like in this topic"
         other: "there are %{count} likes in this topic"
diff --git a/db/post_migrate/20210624023831_remove_highest_seen_post_number_from_topic_users.rb b/db/post_migrate/20210624023831_remove_highest_seen_post_number_from_topic_users.rb
new file mode 100644
index 0000000000..dbf2cdc3e2
--- /dev/null
+++ b/db/post_migrate/20210624023831_remove_highest_seen_post_number_from_topic_users.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require 'migration/column_dropper'
+
+class RemoveHighestSeenPostNumberFromTopicUsers < ActiveRecord::Migration[6.1]
+  DROPPED_COLUMNS = {
+    topic_users: %i{highest_seen_post_number}
+  }
+
+  def up
+    DROPPED_COLUMNS.each do |table, columns|
+      Migration::ColumnDropper.execute_drop(table, columns)
+    end
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end
diff --git a/lib/post_creator.rb b/lib/post_creator.rb
index abc8dc445b..a4f2490a16 100644
--- a/lib/post_creator.rb
+++ b/lib/post_creator.rb
@@ -646,7 +646,6 @@ class PostCreator
                       @topic.id,
                       posted: true,
                       last_read_post_number: @post.post_number,
-                      highest_seen_post_number: @post.post_number,
                       last_posted_at: Time.zone.now)
 
     # assume it took us 5 seconds of reading time to make a post
diff --git a/lib/tasks/import.rake b/lib/tasks/import.rake
index a4552c70c5..861b6d998a 100644
--- a/lib/tasks/import.rake
+++ b/lib/tasks/import.rake
@@ -57,8 +57,8 @@ def insert_topic_users
   log "Inserting topic users..."
 
   DB.exec <<-SQL
-    INSERT INTO topic_users (user_id, topic_id, posted, last_read_post_number, highest_seen_post_number, first_visited_at, last_visited_at, total_msecs_viewed)
-         SELECT user_id, topic_id, 't' , MAX(post_number), MAX(post_number), MIN(created_at), MAX(created_at), COUNT(id) * #{MS_SPEND_CREATING_POST}
+    INSERT INTO topic_users (user_id, topic_id, posted, last_read_post_number, first_visited_at, last_visited_at, total_msecs_viewed)
+         SELECT user_id, topic_id, 't' , MAX(post_number), MIN(created_at), MAX(created_at), COUNT(id) * #{MS_SPEND_CREATING_POST}
            FROM posts
           WHERE user_id > 0
        GROUP BY user_id, topic_id
diff --git a/lib/tasks/posts.rake b/lib/tasks/posts.rake
index 51aed6c96e..4abfaf01a6 100644
--- a/lib/tasks/posts.rake
+++ b/lib/tasks/posts.rake
@@ -346,7 +346,6 @@ task 'posts:reorder_posts', [:topic_id] => [:environment] do |_, args|
       ["post_timings", "post_number"],
       ["posts", "reply_to_post_number"],
       ["topic_users", "last_read_post_number"],
-      ["topic_users", "highest_seen_post_number"],
       ["topic_users", "last_emailed_post_number"],
     ].each do |table, column|
       builder = DB.build <<~SQL
diff --git a/lib/topics_bulk_action.rb b/lib/topics_bulk_action.rb
index 4a9418853f..ad19ac1bcf 100644
--- a/lib/topics_bulk_action.rb
+++ b/lib/topics_bulk_action.rb
@@ -72,7 +72,7 @@ class TopicsBulkAction
     highest_number_source_column = @user.staff? ? 'highest_staff_post_number' : 'highest_post_number'
     sql = <<~SQL
       UPDATE topic_users tu
-      SET highest_seen_post_number = t.#{highest_number_source_column} , last_read_post_number = t.#{highest_number_source_column}
+      SET last_read_post_number = t.#{highest_number_source_column}
       FROM topics t
       WHERE t.id = tu.topic_id AND tu.user_id = :user_id AND t.id IN (:topic_ids)
     SQL
diff --git a/lib/unread.rb b/lib/unread.rb
index 917c2e396d..27c8d046e2 100644
--- a/lib/unread.rb
+++ b/lib/unread.rb
@@ -2,7 +2,7 @@
 
 class Unread
 
-  # This module helps us calculate unread and new post counts
+  # This module helps us calculate unread post counts
 
   def initialize(topic, topic_user, guardian)
     @guardian = guardian
@@ -11,29 +11,27 @@ class Unread
   end
 
   def unread_posts
-    return 0 if do_not_notify?(@topic_user.notification_level)
-    result = ((@topic_user.highest_seen_post_number || 0) - (@topic_user.last_read_post_number || 0))
-    result = 0 if result < 0
-    result
-  end
-
-  def new_posts
-    return 0 if @topic_user.highest_seen_post_number.blank?
+    return 0 if @topic_user.last_read_post_number.blank?
     return 0 if do_not_notify?(@topic_user.notification_level)
 
     highest_post_number = @guardian.is_staff? ? @topic.highest_staff_post_number : @topic.highest_post_number
 
-    return 0 if (@topic_user.last_read_post_number || 0) > highest_post_number
+    return 0 if @topic_user.last_read_post_number > highest_post_number
 
-    new_posts = (highest_post_number - @topic_user.highest_seen_post_number)
-    new_posts = 0 if new_posts < 0
-    new_posts
+    unread = (highest_post_number - @topic_user.last_read_post_number)
+    unread = 0 if unread < 0
+    unread
   end
 
   protected
 
+  DO_NOT_NOTIFY_LEVELS = [
+    TopicUser.notification_levels[:muted],
+    TopicUser.notification_levels[:regular]
+  ]
+
   def do_not_notify?(notification_level)
-    [TopicUser.notification_levels[:muted], TopicUser.notification_levels[:regular]].include?(notification_level)
+    DO_NOT_NOTIFY_LEVELS.include?(notification_level)
   end
 
 end
diff --git a/plugins/discourse-narrative-bot/plugin.rb b/plugins/discourse-narrative-bot/plugin.rb
index 7f3fde2436..d2b790a893 100644
--- a/plugins/discourse-narrative-bot/plugin.rb
+++ b/plugins/discourse-narrative-bot/plugin.rb
@@ -192,7 +192,7 @@ after_initialize do
     return if topic_id.blank? || data[:track] != DiscourseNarrativeBot::NewUserNarrative.to_s
 
     topic_user = topic_users.find_by(topic_id: topic_id)
-    return if topic_user.present? && (topic_user.last_read_post_number.present? || topic_user.highest_seen_post_number.present?)
+    return if topic_user.present? && topic_user.last_read_post_number.present?
 
     topic = Topic.find_by(id: topic_id)
     return if topic.blank?
diff --git a/plugins/poll/test/javascripts/acceptance/poll-in-reply-history-test.js.es6 b/plugins/poll/test/javascripts/acceptance/poll-in-reply-history-test.js.es6
index 12c507d1d5..f2e08b0b46 100644
--- a/plugins/poll/test/javascripts/acceptance/poll-in-reply-history-test.js.es6
+++ b/plugins/poll/test/javascripts/acceptance/poll-in-reply-history-test.js.es6
@@ -150,8 +150,7 @@ acceptance("Poll in a post reply history", function (needs) {
             archetype: "regular",
             unseen: false,
             last_read_post_number: 3,
-            unread: 0,
-            new_posts: 0,
+            unread_posts: 0,
             pinned: false,
             unpinned: null,
             visible: true,
@@ -205,8 +204,7 @@ acceptance("Poll in a post reply history", function (needs) {
             archetype: "regular",
             unseen: false,
             last_read_post_number: 12,
-            unread: 0,
-            new_posts: 0,
+            unread_posts: 0,
             pinned: false,
             unpinned: null,
             visible: true,
diff --git a/plugins/poll/test/javascripts/acceptance/poll-quote-test.js.es6 b/plugins/poll/test/javascripts/acceptance/poll-quote-test.js.es6
index 3b5bb2ddac..f000d468e0 100644
--- a/plugins/poll/test/javascripts/acceptance/poll-quote-test.js.es6
+++ b/plugins/poll/test/javascripts/acceptance/poll-quote-test.js.es6
@@ -230,8 +230,7 @@ acceptance("Poll quote", function (needs) {
             archetype: "regular",
             unseen: false,
             last_read_post_number: 1,
-            unread: 0,
-            new_posts: 0,
+            unread_posts: 0,
             pinned: false,
             unpinned: true,
             visible: true,
@@ -275,8 +274,7 @@ acceptance("Poll quote", function (needs) {
             archetype: "regular",
             unseen: false,
             last_read_post_number: 1,
-            unread: 0,
-            new_posts: 0,
+            unread_posts: 0,
             pinned: false,
             unpinned: null,
             visible: true,
diff --git a/plugins/poll/test/javascripts/acceptance/poll-results-test.js.es6 b/plugins/poll/test/javascripts/acceptance/poll-results-test.js.es6
index 30a7889d43..4a029002ed 100644
--- a/plugins/poll/test/javascripts/acceptance/poll-results-test.js.es6
+++ b/plugins/poll/test/javascripts/acceptance/poll-results-test.js.es6
@@ -239,8 +239,7 @@ acceptance("Poll results", function (needs) {
             archetype: "regular",
             unseen: false,
             last_read_post_number: 9,
-            unread: 0,
-            new_posts: 0,
+            unread_posts: 0,
             pinned: false,
             unpinned: true,
             visible: true,
@@ -295,8 +294,7 @@ acceptance("Poll results", function (needs) {
             archetype: "regular",
             unseen: false,
             last_read_post_number: 1,
-            unread: 0,
-            new_posts: 0,
+            unread_posts: 0,
             pinned: false,
             unpinned: null,
             visible: true,
@@ -343,8 +341,7 @@ acceptance("Poll results", function (needs) {
             archetype: "regular",
             unseen: false,
             last_read_post_number: 1,
-            unread: 0,
-            new_posts: 0,
+            unread_posts: 0,
             pinned: false,
             unpinned: null,
             visible: true,
@@ -389,8 +386,7 @@ acceptance("Poll results", function (needs) {
             archetype: "regular",
             unseen: false,
             last_read_post_number: 12,
-            unread: 0,
-            new_posts: 0,
+            unread_posts: 0,
             pinned: false,
             unpinned: null,
             visible: true,
diff --git a/script/import_scripts/base.rb b/script/import_scripts/base.rb
index a88360941a..7cd7961cfc 100644
--- a/script/import_scripts/base.rb
+++ b/script/import_scripts/base.rb
@@ -762,8 +762,8 @@ class ImportScripts::Base
     puts "", "Updating topic users"
 
     DB.exec <<~SQL
-      INSERT INTO topic_users (user_id, topic_id, posted, last_read_post_number, highest_seen_post_number, first_visited_at, last_visited_at, total_msecs_viewed)
-           SELECT user_id, topic_id, 't' , MAX(post_number), MAX(post_number), MIN(created_at), MAX(created_at), COUNT(id) * 5000
+      INSERT INTO topic_users (user_id, topic_id, posted, last_read_post_number, first_visited_at, last_visited_at, total_msecs_viewed)
+           SELECT user_id, topic_id, 't' , MAX(post_number), MIN(created_at), MAX(created_at), COUNT(id) * 5000
              FROM posts
             WHERE user_id > 0
          GROUP BY user_id, topic_id
diff --git a/script/import_scripts/telligent.rb b/script/import_scripts/telligent.rb
index a6b1218e41..32ffda8acb 100644
--- a/script/import_scripts/telligent.rb
+++ b/script/import_scripts/telligent.rb
@@ -598,8 +598,7 @@ class ImportScripts::Telligent < ImportScripts::Base
     # Mark all imported messages as read
     DB.exec(<<~SQL)
       UPDATE topic_users tu
-      SET last_read_post_number = t.highest_post_number,
-          highest_seen_post_number = t.highest_post_number
+      SET last_read_post_number = t.highest_post_number
       FROM topics t
         JOIN topic_custom_fields tcf ON t.id = tcf.topic_id
       WHERE tu.topic_id = t.id
diff --git a/spec/components/post_destroyer_spec.rb b/spec/components/post_destroyer_spec.rb
index 66ae44a83f..e9a005d6f0 100644
--- a/spec/components/post_destroyer_spec.rb
+++ b/spec/components/post_destroyer_spec.rb
@@ -652,10 +652,6 @@ describe PostDestroyer do
       it "sets the second user's last_read_post_number back to 1" do
         expect(topic_user.last_read_post_number).to eq(1)
       end
-
-      it "sets the second user's last_read_post_number back to 1" do
-        expect(topic_user.highest_seen_post_number).to eq(1)
-      end
     end
   end
 
diff --git a/spec/components/topics_bulk_action_spec.rb b/spec/components/topics_bulk_action_spec.rb
index c096a5a19f..169af2603d 100644
--- a/spec/components/topics_bulk_action_spec.rb
+++ b/spec/components/topics_bulk_action_spec.rb
@@ -82,7 +82,6 @@ describe TopicsBulkAction do
       tu = TopicUser.find_by(user_id: post1.user_id, topic_id: post1.topic_id)
 
       expect(tu.last_read_post_number).to eq(3)
-      expect(tu.highest_seen_post_number).to eq(3)
     end
 
     context "when the user is staff" do
@@ -106,7 +105,6 @@ describe TopicsBulkAction do
           tu = TopicUser.find_by(user_id: user.id, topic_id: post1.topic_id)
 
           expect(tu.last_read_post_number).to eq(4)
-          expect(tu.highest_seen_post_number).to eq(4)
         end
       end
     end
diff --git a/spec/components/unread_spec.rb b/spec/components/unread_spec.rb
index a7d4d4a65e..cf112df130 100644
--- a/spec/components/unread_spec.rb
+++ b/spec/components/unread_spec.rb
@@ -27,62 +27,45 @@ describe Unread do
 
   describe 'staff counts' do
     it 'should correctly return based on staff post number' do
-
       user.admin = true
 
       topic_user.last_read_post_number = 13
-      topic_user.highest_seen_post_number = 13
 
-      expect(unread.unread_posts).to eq(0)
-      expect(unread.new_posts).to eq(2)
+      expect(unread.unread_posts).to eq(2)
     end
   end
 
   describe 'unread_posts' do
-    it 'should have 0 unread posts if the user has seen all posts' do
+    it 'should have 0 unread posts if the user has read all posts' do
       topic_user.last_read_post_number = 13
-      topic_user.highest_seen_post_number = 13
       expect(unread.unread_posts).to eq(0)
     end
 
-    it 'should have 6 unread posts if the user has seen all but 6 posts' do
-      topic_user.last_read_post_number = 5
-      topic_user.highest_seen_post_number = 11
-      expect(unread.unread_posts).to eq(6)
+    it 'returns the right unread posts for a user' do
+      topic_user.last_read_post_number = 10
+      expect(unread.unread_posts).to eq(3)
     end
 
-    it 'should have 0 unread posts if the user has seen more posts than exist (deleted)' do
-      topic_user.last_read_post_number = 100
-      topic_user.highest_seen_post_number = 13
+    it 'returns the right unread posts for a staff user' do
+      user.admin = true
+      topic_user.last_read_post_number = 10
+      expect(unread.unread_posts).to eq(5)
+    end
+
+    it 'should have 0 unread posts if the user has read more posts than exist (deleted)' do
+      topic_user.last_read_post_number = 14
       expect(unread.unread_posts).to eq(0)
     end
-  end
 
-  describe 'new_posts' do
-    it 'should have 0 new posts if the user has read all posts' do
-      topic_user.last_read_post_number = 13
-      expect(unread.new_posts).to eq(0)
-    end
-
-    it 'returns 0 when the topic is the same length as when you last saw it' do
-      topic_user.highest_seen_post_number = 13
-      expect(unread.new_posts).to eq(0)
-    end
-
-    it 'has 3 new posts if the user has read 10 posts' do
-      topic_user.highest_seen_post_number = 10
-      expect(unread.new_posts).to eq(3)
-    end
-
-    it 'has 0 new posts if the user has read 10 posts but is not tracking' do
-      topic_user.highest_seen_post_number = 10
+    it 'has 0 unread posts if the user has read 10 posts but is not tracking' do
+      topic_user.last_read_post_number = 10
       topic_user.notification_level = TopicUser.notification_levels[:regular]
-      expect(unread.new_posts).to eq(0)
+      expect(unread.unread_posts).to eq(0)
     end
 
-    it 'has 0 new posts if the user read more posts than exist (deleted)' do
-      topic_user.highest_seen_post_number = 16
-      expect(unread.new_posts).to eq(0)
+    it 'has 0 unread psots if the user has not seen the topic' do
+      topic_user.last_read_post_number = nil
+      expect(unread.unread_posts).to eq(0)
     end
   end
 
diff --git a/spec/fixtures/json/sam-s-simple-theme.dcstyle.json b/spec/fixtures/json/sam-s-simple-theme.dcstyle.json
index e942c38689..103fae676f 100644
--- a/spec/fixtures/json/sam-s-simple-theme.dcstyle.json
+++ b/spec/fixtures/json/sam-s-simple-theme.dcstyle.json
@@ -1 +1 @@
-{"theme":{"id":2,"name":"Sam's Simple Theme","key":"6a390523-b662-4966-97d6-e731d292cd9d","created_at":"2017-05-08T06:17:14.510Z","updated_at":"2017-05-08T06:17:14.510Z","color_scheme":null,"color_scheme_id":null,"user_selectable":false,"remote_theme_id":1,"theme_fields":[{"name":"scss","target":"desktop","value":".topic-list \u003e tbody \u003e tr:nth-child(odd) {\n    background-color: white;\n}\n\n\n.topic-list \u003e tbody tr:not(.last-visit):not(.topic-list-item-separator) td {\n    border-bottom: 1px solid #eee;\n}\n\n.topic-list a.title:not(.badge-notification) {\n    color: #3b5998;\n    font-weight: normal;\n    font-family: 'Helvetica Neue', Helvetica, Arial, Utkal, sans-serif;\n    font-size: 18px;\n}\n\n.topic-list a.title:not(.badge-notification):hover {\n    text-decoration: underline;\n}\n\n.topic-list .creator, .topic-list .editor {\n    font-size: 13px;\n    display: block;\n    margin-top: 3px;\n}\n\n.topic-list .main-link {\n    width: auto;\n}\n\n.topic-list {\n    td, .creator a, .editor a {\n        color: #888;\n    }\n}\n\n.topic-list td {\n    padding-bottom: 10px;\n}\n\n.topic-list th {\n    color: black;\n    background-color: #fafafa;\n}\n.topic-list {\n    border-top: none;\n}\n\n.topic-list td:first-of-type {\n    padding-bottom: 10px;\n    padding-left: 10px;\n    padding-top: 10px;\n}\n\n.topic-list tr.topic-list-item-separator td:first-of-type {\n    padding: 0;\n}\n\n \n.topic-list {\n    .fa-tag {\n        opacity: 0.7;\n        font-size: 10px;\n        margin-right: -2px;\n    }\n    .num.posts-map {\n        position: relative;\n        font-size: 17px;\n        a {\n            color: #888 !important;\n            font-weight: normal;\n        }\n        a.heatmap-high {\n            color: #c66 !important;   \n        }\n        width: 100px;\n    }\n}\n\n.topic-list td.last-post, .topic-list th.activity {\n    width: 160px;\n    .relative-date {\n        color: #666;\n    }\n}\n\n.topic-list .creator .relative-date {\n    margin-left: 8px;\n}\n\n.badge-category-bg {\n    opacity: 0.8;\n}\n\n.topic-list .badge-wrapper.bar {\n    .badge-category {\n      color: #9a9a9a !important;\n      font-weight: 600;\n      font-size: 12px;\n      padding: 2px 6px;\n    }\n    .badge-category-bg {\n        top: -1px;\n    }\n}\n\n.last-post {\n    .poster-avatar {\n        margin-right: 10px;\n    }\n    .poster-avatar, .poster-info {\n        float: left;\n    }\n}\n\n.topic-list .posts {\n    width: auto;\n}\n\n/* topic page */\n#topic-progress {\n    background-color: #f1f1f1;\n    color: #666;\n    font-weight: normal;\n    .bg {\n       background-color: #bee9e9;\n    }\n}\n\nnav.post-controls button.has-like {\n    color: #08c;\n}\n\n.title-wrapper .discourse-tag {\n    border-radius: 5px !important;\n    border: 0px solid #D0D0D0 !important;\n    padding: 1px 6px !important;\n    color: #1D1D1D !important;\n    background-color: #F1F1F1 !important;\n}\n\n.badge-wrapper.bullet span.badge-category {\n    color: #333 !important;\n}\n\n.creator .badge-wrapper.bullet span.badge-category {\n    color: #888 !important;\n    margin-top: -2px;\n}\n\nimg.avatar {\n    border-radius: 3px;\n}\n\n#suggested-topics td.main-link {\n    width: 500px;\n}\n\n.topic-list a.title.visited:not(.badge-notification) {\n    color: #6644aa;\n}\n"},{"name":"header","target":"desktop","value":"\u003cscript type='text/x-handlebars' data-template-name='list/topic-list-item.raw'\u003e\n\n\u003ctd class='main-link clearfix'\u003e\n\n  {{raw \"topic-status\" topic=topic}}\n  {{topic-link topic}}\n  {{#if controller.showTopicPostBadges}}\n    {{raw \"topic-post-badges\" unread=topic.unread newPosts=topic.displayNewPosts unseen=topic.unseen url=topic.lastUnreadUrl}}\n  {{/if}}\n\n\n  {{raw \"list/topic-excerpt\" topic=model}}\n  \u003cdiv class='creator'\u003e\n  {{#if showCategory}}\n     {{category-link topic.category}}\n   {{/if}}\n  {{~#if topic.creator ~}}\n  \u003ca href=\"/users/{{topic.creator.username}}\" data-auto-route=\"true\" data-user-card=\"{{topic.creator.username}}\"\u003e{{topic.creator.username}}\u003c/a\u003e \u003ca href={{topic.url}}\u003e{{format-date topic.createdAt format=\"tiny\"}}\u003c/a\u003e\n  {{~/if ~}}\n   {{raw \"list/action-list\" topic=topic postNumbers=topic.liked_post_numbers className=\"likes\" icon=\"heart\"}}\n   \u003c/div\u003e\n\u003c/td\u003e\n\n\n\n{{#if controller.showLikes}}\n\u003ctd class=\"num likes\"\u003e\n  {{number topic.like_count}} \u003ci class='fa fa-heart'\u003e\u003c/i\u003e\n\u003c/td\u003e\n{{/if}}\n   \n{{#if controller.showOpLikes}}\n\u003ctd class=\"num likes\"\u003e\n  {{number topic.op_like_count}} \u003ci class='fa fa-heart'\u003e\u003c/i\u003e\n\u003c/td\u003e\n{{/if}}\n\n{{raw \"list/posts-count-column\" topic=topic}}\n\n\u003ctd class=\"last-post\"\u003e\n\u003cdiv class='poster-avatar'\u003e\n\u003ca href=\"{{topic.lastPostUr}}\" data-user-card=\"{{topic.last_poster_username}}\"\u003e{{avatar topic.lastPoster usernamePath=\"username\" imageSize=\"medium\"}}\u003c/a\u003e\n\u003c/div\u003e\n\u003cdiv class='poster-info'\u003e\n\u003ca href=\"{{topic.lastPostUrl}}\"\u003e\n{{format-date topic.bumpedAt format=\"tiny\"}}\n\u003c/a\u003e\n\u003cspan class='editor'\u003e\u003ca href=\"/users/{{topic.last_poster_username}}\" data-auto-route=\"true\" data-user-card=\"{{topic.last_poster_username}}\"\u003e{{topic.last_poster_username}}\u003c/a\u003e\u003c/span\u003e\n\u003c/div\u003e\n\u003c/td\u003e\n\u003c/script\u003e\n\n\u003cscript type='text/x-handlebars' data-template-name='topic-list-header.raw'\u003e\n  {{raw \"topic-list-header-column\" order='posts' name='topic.title'}}\n  \n  {{#if showLikes}}\n     {{raw \"topic-list-header-column\" sortable='true' order='likes' number='true' forceName='Likes'}}\n  {{/if}}\n  {{#if showOpLikes}}\n     {{raw \"topic-list-header-column\" sortable='true' order='op_likes' number='true' forceName='Likes'}}\n  {{/if}}\n  {{raw \"topic-list-header-column\" sortable='true' number='true' order='posts' forceName='Replies'}}\n  {{raw \"topic-list-header-column\" sortable='true' order='activity' forceName='Last Post'}}\n\u003c/script\u003e\n\n\u003cscript\u003e\n\n(function(){\n\nvar TopicListItemView = require('discourse/components/topic-list-item').default;\n\n\nTopicListItemView.reopen({\n    showCategory: function(){\n        return !this.get('controller.hideCategory') \u0026\u0026\n                this.get('topic.creator') \u0026\u0026\n                this.get('topic.category.name') !== 'uncategorized';\n    }.property()\n});\n   \n})();\n \n\u003c/script\u003e\n"}],"child_themes":[],"remote_theme":{"id":1,"remote_url":"https://github.com/SamSaffron/discourse-simple-theme.git","remote_version":"49986016d76be1f526d5dc44704e6701021db900","local_version":"49986016d76be1f526d5dc44704e6701021db900","about_url":"https://meta.discourse.org/t/sams-personal-minimal-topic-list-design/23552","license_url":"https://github.com/SamSaffron/discourse-simple-theme/blob/master/LICENSE.txt","commits_behind":0,"remote_updated_at":"2017-05-08T06:17:14.487Z","updated_at":"2017-05-08T06:17:14.501Z"}}}
+{"theme":{"id":2,"name":"Sam's Simple Theme","key":"6a390523-b662-4966-97d6-e731d292cd9d","created_at":"2017-05-08T06:17:14.510Z","updated_at":"2017-05-08T06:17:14.510Z","color_scheme":null,"color_scheme_id":null,"user_selectable":false,"remote_theme_id":1,"theme_fields":[{"name":"scss","target":"desktop","value":".topic-list \u003e tbody \u003e tr:nth-child(odd) {\n    background-color: white;\n}\n\n\n.topic-list \u003e tbody tr:not(.last-visit):not(.topic-list-item-separator) td {\n    border-bottom: 1px solid #eee;\n}\n\n.topic-list a.title:not(.badge-notification) {\n    color: #3b5998;\n    font-weight: normal;\n    font-family: 'Helvetica Neue', Helvetica, Arial, Utkal, sans-serif;\n    font-size: 18px;\n}\n\n.topic-list a.title:not(.badge-notification):hover {\n    text-decoration: underline;\n}\n\n.topic-list .creator, .topic-list .editor {\n    font-size: 13px;\n    display: block;\n    margin-top: 3px;\n}\n\n.topic-list .main-link {\n    width: auto;\n}\n\n.topic-list {\n    td, .creator a, .editor a {\n        color: #888;\n    }\n}\n\n.topic-list td {\n    padding-bottom: 10px;\n}\n\n.topic-list th {\n    color: black;\n    background-color: #fafafa;\n}\n.topic-list {\n    border-top: none;\n}\n\n.topic-list td:first-of-type {\n    padding-bottom: 10px;\n    padding-left: 10px;\n    padding-top: 10px;\n}\n\n.topic-list tr.topic-list-item-separator td:first-of-type {\n    padding: 0;\n}\n\n \n.topic-list {\n    .fa-tag {\n        opacity: 0.7;\n        font-size: 10px;\n        margin-right: -2px;\n    }\n    .num.posts-map {\n        position: relative;\n        font-size: 17px;\n        a {\n            color: #888 !important;\n            font-weight: normal;\n        }\n        a.heatmap-high {\n            color: #c66 !important;   \n        }\n        width: 100px;\n    }\n}\n\n.topic-list td.last-post, .topic-list th.activity {\n    width: 160px;\n    .relative-date {\n        color: #666;\n    }\n}\n\n.topic-list .creator .relative-date {\n    margin-left: 8px;\n}\n\n.badge-category-bg {\n    opacity: 0.8;\n}\n\n.topic-list .badge-wrapper.bar {\n    .badge-category {\n      color: #9a9a9a !important;\n      font-weight: 600;\n      font-size: 12px;\n      padding: 2px 6px;\n    }\n    .badge-category-bg {\n        top: -1px;\n    }\n}\n\n.last-post {\n    .poster-avatar {\n        margin-right: 10px;\n    }\n    .poster-avatar, .poster-info {\n        float: left;\n    }\n}\n\n.topic-list .posts {\n    width: auto;\n}\n\n/* topic page */\n#topic-progress {\n    background-color: #f1f1f1;\n    color: #666;\n    font-weight: normal;\n    .bg {\n       background-color: #bee9e9;\n    }\n}\n\nnav.post-controls button.has-like {\n    color: #08c;\n}\n\n.title-wrapper .discourse-tag {\n    border-radius: 5px !important;\n    border: 0px solid #D0D0D0 !important;\n    padding: 1px 6px !important;\n    color: #1D1D1D !important;\n    background-color: #F1F1F1 !important;\n}\n\n.badge-wrapper.bullet span.badge-category {\n    color: #333 !important;\n}\n\n.creator .badge-wrapper.bullet span.badge-category {\n    color: #888 !important;\n    margin-top: -2px;\n}\n\nimg.avatar {\n    border-radius: 3px;\n}\n\n#suggested-topics td.main-link {\n    width: 500px;\n}\n\n.topic-list a.title.visited:not(.badge-notification) {\n    color: #6644aa;\n}\n"},{"name":"header","target":"desktop","value":"\u003cscript type='text/x-handlebars' data-template-name='list/topic-list-item.raw'\u003e\n\n\u003ctd class='main-link clearfix'\u003e\n\n  {{raw \"topic-status\" topic=topic}}\n  {{topic-link topic}}\n  {{#if controller.showTopicPostBadges}}\n    {{raw \"topic-post-badges\" unreadPosts=topic.unread_posts unseen=topic.unseen url=topic.lastUnreadUrl}}\n  {{/if}}\n\n\n  {{raw \"list/topic-excerpt\" topic=model}}\n  \u003cdiv class='creator'\u003e\n  {{#if showCategory}}\n     {{category-link topic.category}}\n   {{/if}}\n  {{~#if topic.creator ~}}\n  \u003ca href=\"/users/{{topic.creator.username}}\" data-auto-route=\"true\" data-user-card=\"{{topic.creator.username}}\"\u003e{{topic.creator.username}}\u003c/a\u003e \u003ca href={{topic.url}}\u003e{{format-date topic.createdAt format=\"tiny\"}}\u003c/a\u003e\n  {{~/if ~}}\n   {{raw \"list/action-list\" topic=topic postNumbers=topic.liked_post_numbers className=\"likes\" icon=\"heart\"}}\n   \u003c/div\u003e\n\u003c/td\u003e\n\n\n\n{{#if controller.showLikes}}\n\u003ctd class=\"num likes\"\u003e\n  {{number topic.like_count}} \u003ci class='fa fa-heart'\u003e\u003c/i\u003e\n\u003c/td\u003e\n{{/if}}\n   \n{{#if controller.showOpLikes}}\n\u003ctd class=\"num likes\"\u003e\n  {{number topic.op_like_count}} \u003ci class='fa fa-heart'\u003e\u003c/i\u003e\n\u003c/td\u003e\n{{/if}}\n\n{{raw \"list/posts-count-column\" topic=topic}}\n\n\u003ctd class=\"last-post\"\u003e\n\u003cdiv class='poster-avatar'\u003e\n\u003ca href=\"{{topic.lastPostUr}}\" data-user-card=\"{{topic.last_poster_username}}\"\u003e{{avatar topic.lastPoster usernamePath=\"username\" imageSize=\"medium\"}}\u003c/a\u003e\n\u003c/div\u003e\n\u003cdiv class='poster-info'\u003e\n\u003ca href=\"{{topic.lastPostUrl}}\"\u003e\n{{format-date topic.bumpedAt format=\"tiny\"}}\n\u003c/a\u003e\n\u003cspan class='editor'\u003e\u003ca href=\"/users/{{topic.last_poster_username}}\" data-auto-route=\"true\" data-user-card=\"{{topic.last_poster_username}}\"\u003e{{topic.last_poster_username}}\u003c/a\u003e\u003c/span\u003e\n\u003c/div\u003e\n\u003c/td\u003e\n\u003c/script\u003e\n\n\u003cscript type='text/x-handlebars' data-template-name='topic-list-header.raw'\u003e\n  {{raw \"topic-list-header-column\" order='posts' name='topic.title'}}\n  \n  {{#if showLikes}}\n     {{raw \"topic-list-header-column\" sortable='true' order='likes' number='true' forceName='Likes'}}\n  {{/if}}\n  {{#if showOpLikes}}\n     {{raw \"topic-list-header-column\" sortable='true' order='op_likes' number='true' forceName='Likes'}}\n  {{/if}}\n  {{raw \"topic-list-header-column\" sortable='true' number='true' order='posts' forceName='Replies'}}\n  {{raw \"topic-list-header-column\" sortable='true' order='activity' forceName='Last Post'}}\n\u003c/script\u003e\n\n\u003cscript\u003e\n\n(function(){\n\nvar TopicListItemView = require('discourse/components/topic-list-item').default;\n\n\nTopicListItemView.reopen({\n    showCategory: function(){\n        return !this.get('controller.hideCategory') \u0026\u0026\n                this.get('topic.creator') \u0026\u0026\n                this.get('topic.category.name') !== 'uncategorized';\n    }.property()\n});\n   \n})();\n \n\u003c/script\u003e\n"}],"child_themes":[],"remote_theme":{"id":1,"remote_url":"https://github.com/SamSaffron/discourse-simple-theme.git","remote_version":"49986016d76be1f526d5dc44704e6701021db900","local_version":"49986016d76be1f526d5dc44704e6701021db900","about_url":"https://meta.discourse.org/t/sams-personal-minimal-topic-list-design/23552","license_url":"https://github.com/SamSaffron/discourse-simple-theme/blob/master/LICENSE.txt","commits_behind":0,"remote_updated_at":"2017-05-08T06:17:14.487Z","updated_at":"2017-05-08T06:17:14.501Z"}}}
diff --git a/spec/models/post_mover_spec.rb b/spec/models/post_mover_spec.rb
index 6c3e3a43ef..e5e26d2c33 100644
--- a/spec/models/post_mover_spec.rb
+++ b/spec/models/post_mover_spec.rb
@@ -425,7 +425,6 @@ describe PostMover do
               bookmarked: true,
               notification_level: TopicUser.notification_levels[:watching],
               last_read_post_number: 4,
-              highest_seen_post_number: 4,
               last_emailed_post_number: 3
             )
             tu2 = Fabricate(
@@ -435,7 +434,6 @@ describe PostMover do
               bookmarked: true,
               notification_level: TopicUser.notification_levels[:watching],
               last_read_post_number: 4,
-              highest_seen_post_number: 4,
               last_emailed_post_number: 3
             )
 
@@ -470,21 +468,18 @@ describe PostMover do
               create_topic_user(
                 user1,
                 last_read_post_number: 4,
-                highest_seen_post_number: 4,
                 last_emailed_post_number: 3,
                 notification_level: :tracking
               )
               create_topic_user(
                 user2,
                 last_read_post_number: 2,
-                highest_seen_post_number: 2,
                 last_emailed_post_number: 2,
                 notification_level: :tracking
               )
               create_topic_user(
                 user3,
                 last_read_post_number: 1,
-                highest_seen_post_number: 2,
                 last_emailed_post_number: 4,
                 notification_level: :watching
               )
@@ -496,28 +491,24 @@ describe PostMover do
               expect(TopicUser.find_by(topic: topic, user: user))
                 .to have_attributes(
                       last_read_post_number: 4,
-                      highest_seen_post_number: 4,
                       last_emailed_post_number: nil,
                       notification_level: TopicUser.notification_levels[:tracking]
                     )
               expect(TopicUser.find_by(topic: topic, user: user1))
                 .to have_attributes(
                       last_read_post_number: 4,
-                      highest_seen_post_number: 4,
                       last_emailed_post_number: 3,
                       notification_level: TopicUser.notification_levels[:tracking]
                     )
               expect(TopicUser.find_by(topic: topic, user: user2))
                 .to have_attributes(
                       last_read_post_number: 2,
-                      highest_seen_post_number: 2,
                       last_emailed_post_number: 2,
                       notification_level: TopicUser.notification_levels[:tracking]
                     )
               expect(TopicUser.find_by(topic: topic, user: user3))
                 .to have_attributes(
                       last_read_post_number: 1,
-                      highest_seen_post_number: 2,
                       last_emailed_post_number: 4,
                       notification_level: TopicUser.notification_levels[:watching]
                     )
@@ -526,7 +517,6 @@ describe PostMover do
               expect(TopicUser.find_by(topic: new_topic, user: user))
                 .to have_attributes(
                       last_read_post_number: 1,
-                      highest_seen_post_number: 1,
                       last_emailed_post_number: nil,
                       notification_level: TopicUser.notification_levels[:watching],
                       posted: true
@@ -534,7 +524,6 @@ describe PostMover do
               expect(TopicUser.find_by(topic: new_topic, user: user1))
                 .to have_attributes(
                       last_read_post_number: 2,
-                      highest_seen_post_number: 2,
                       last_emailed_post_number: 2,
                       notification_level: TopicUser.notification_levels[:tracking],
                       posted: false
@@ -542,7 +531,6 @@ describe PostMover do
               expect(TopicUser.find_by(topic: new_topic, user: user2))
                 .to have_attributes(
                       last_read_post_number: 2,
-                      highest_seen_post_number: 2,
                       last_emailed_post_number: 2,
                       notification_level: TopicUser.notification_levels[:tracking],
                       posted: true
@@ -550,7 +538,6 @@ describe PostMover do
               expect(TopicUser.find_by(topic: new_topic, user: user3))
                 .to have_attributes(
                       last_read_post_number: 1,
-                      highest_seen_post_number: 2,
                       last_emailed_post_number: 2,
                       notification_level: TopicUser.notification_levels[:watching],
                       posted: false
@@ -810,52 +797,44 @@ describe PostMover do
               create_topic_user(
                 user1, topic,
                 last_read_post_number: 3,
-                highest_seen_post_number: 3,
                 last_emailed_post_number: 3
               )
               create_topic_user(
                 user1, destination_topic,
                 last_read_post_number: 1,
-                highest_seen_post_number: 2,
                 last_emailed_post_number: 1
               )
 
               create_topic_user(
                 user2, topic,
                 last_read_post_number: 3,
-                highest_seen_post_number: 3,
                 last_emailed_post_number: 3
               )
               create_topic_user(
                 user2, destination_topic,
                 last_read_post_number: 2,
-                highest_seen_post_number: 1,
                 last_emailed_post_number: 2
               )
 
               create_topic_user(
                 admin1, topic,
                 last_read_post_number: 3,
-                highest_seen_post_number: 3,
                 last_emailed_post_number: 3
               )
               create_topic_user(
                 admin1, destination_topic,
                 last_read_post_number: 2,
-                highest_seen_post_number: 3,
                 last_emailed_post_number: 1
               )
 
               create_topic_user(
                 admin2, topic,
                 last_read_post_number: 3,
-                highest_seen_post_number: 3,
                 last_emailed_post_number: 3
               )
               create_topic_user(
                 admin2, destination_topic,
                 last_read_post_number: 3,
-                highest_seen_post_number: 2,
                 last_emailed_post_number: 3
               )
 
@@ -864,28 +843,24 @@ describe PostMover do
               expect(TopicUser.find_by(topic: moved_to_topic, user: user1))
                 .to have_attributes(
                       last_read_post_number: 1,
-                      highest_seen_post_number: 5,
                       last_emailed_post_number: 1
                     )
 
               expect(TopicUser.find_by(topic: moved_to_topic, user: user2))
                 .to have_attributes(
                       last_read_post_number: 5,
-                      highest_seen_post_number: 1,
                       last_emailed_post_number: 5
                     )
 
               expect(TopicUser.find_by(topic: moved_to_topic, user: admin1))
                 .to have_attributes(
                       last_read_post_number: 2,
-                      highest_seen_post_number: 5,
                       last_emailed_post_number: 1
                     )
 
               expect(TopicUser.find_by(topic: moved_to_topic, user: admin2))
                 .to have_attributes(
                       last_read_post_number: 5,
-                      highest_seen_post_number: 2,
                       last_emailed_post_number: 5
                     )
             end
@@ -895,14 +870,14 @@ describe PostMover do
 
               original_topic_user1 = create_topic_user(
                 user1, topic,
-                highest_seen_post_number: 5,
+                last_read_post_number: 5,
                 first_visited_at: 5.hours.ago,
                 last_visited_at: 30.minutes.ago,
                 notification_level: :tracking
               ).reload
               destination_topic_user1 = create_topic_user(
                 user1, destination_topic,
-                highest_seen_post_number: 5,
+                last_read_post_number: 5,
                 first_visited_at: 7.hours.ago,
                 last_visited_at: 2.hours.ago,
                 notification_level: :watching
@@ -910,14 +885,14 @@ describe PostMover do
 
               original_topic_user2 = create_topic_user(
                 user2, topic,
-                highest_seen_post_number: 5,
+                last_read_post_number: 5,
                 first_visited_at: 3.hours.ago,
                 last_visited_at: 1.hour.ago,
                 notification_level: :watching
               ).reload
               destination_topic_user2 = create_topic_user(
                 user2, destination_topic,
-                highest_seen_post_number: 5,
+                last_read_post_number: 5,
                 first_visited_at: 2.hours.ago,
                 last_visited_at: 1.hour.ago,
                 notification_level: :tracking
diff --git a/spec/models/post_timing_spec.rb b/spec/models/post_timing_spec.rb
index fbcb8cf3a6..f00c0f65b1 100644
--- a/spec/models/post_timing_spec.rb
+++ b/spec/models/post_timing_spec.rb
@@ -20,12 +20,11 @@ describe PostTiming do
       PostTiming.create!(topic_id: topic_id, user_id: user_id, post_number: post_number, msecs: 0)
     end
 
-    def topic_user(user_id, last_read_post_number, highest_seen_post_number)
+    def topic_user(user_id, last_read_post_number)
       TopicUser.create!(
                         topic_id: topic_id,
                         user_id: user_id,
                         last_read_post_number: last_read_post_number,
-                        highest_seen_post_number: highest_seen_post_number
                        )
     end
 
@@ -37,9 +36,9 @@ describe PostTiming do
       timing(3, 2)
       timing(3, 3)
 
-      _tu_one = topic_user(1, 1, 1)
-      _tu_two = topic_user(2, 2, 2)
-      _tu_three = topic_user(3, 3, 3)
+      _tu_one = topic_user(1, 1)
+      _tu_two = topic_user(2, 2)
+      _tu_three = topic_user(3, 3)
 
       PostTiming.pretend_read(topic_id, 2, 3)
 
@@ -49,15 +48,12 @@ describe PostTiming do
 
       tu = TopicUser.find_by(topic_id: topic_id, user_id: 1)
       expect(tu.last_read_post_number).to eq(1)
-      expect(tu.highest_seen_post_number).to eq(1)
 
       tu = TopicUser.find_by(topic_id: topic_id, user_id: 2)
       expect(tu.last_read_post_number).to eq(3)
-      expect(tu.highest_seen_post_number).to eq(3)
 
       tu = TopicUser.find_by(topic_id: topic_id, user_id: 3)
       expect(tu.last_read_post_number).to eq(3)
-      expect(tu.highest_seen_post_number).to eq(3)
 
     end
   end
diff --git a/spec/models/topic_spec.rb b/spec/models/topic_spec.rb
index efd5a6026c..9798b931a3 100644
--- a/spec/models/topic_spec.rb
+++ b/spec/models/topic_spec.rb
@@ -1615,7 +1615,12 @@ describe Topic do
           end
 
           it 'should generate the modified notification for the topic if already seen' do
-            TopicUser.create!(topic_id: topic.id, highest_seen_post_number: topic.posts.first.post_number, user_id: user.id)
+            TopicUser.create!(
+              topic_id: topic.id,
+              last_read_post_number: topic.posts.first.post_number,
+              user_id: user.id
+            )
+
             expect do
               topic.change_category_to_id(new_category.id)
             end.to change { Notification.count }.by(2)
diff --git a/spec/models/topic_tracking_state_spec.rb b/spec/models/topic_tracking_state_spec.rb
index f87eb2cbff..26e3d2c266 100644
--- a/spec/models/topic_tracking_state_spec.rb
+++ b/spec/models/topic_tracking_state_spec.rb
@@ -597,7 +597,6 @@ describe TopicTrackingState do
     tracking = {
       notification_level: TopicUser.notification_levels[:tracking],
       last_read_post_number: 1,
-      highest_seen_post_number: 1
     }
 
     TopicUser.change(user.id, post1.topic_id, tracking)
diff --git a/spec/models/topic_user_spec.rb b/spec/models/topic_user_spec.rb
index cba1710533..e0b770ada3 100644
--- a/spec/models/topic_user_spec.rb
+++ b/spec/models/topic_user_spec.rb
@@ -434,7 +434,7 @@ describe TopicUser do
     p2 = Fabricate(:post, user: p1.user, topic: p1.topic, post_number: 2)
     p1.topic.notifier.watch_topic!(p1.user_id)
 
-    DB.exec("UPDATE topic_users set highest_seen_post_number=1, last_read_post_number=0
+    DB.exec("UPDATE topic_users set last_read_post_number=0
                        WHERE topic_id = :topic_id AND user_id = :user_id", topic_id: p1.topic_id, user_id: p1.user_id)
 
     [p1, p2].each do |p|
@@ -445,7 +445,6 @@ describe TopicUser do
 
     tu = TopicUser.find_by(user_id: p1.user_id, topic_id: p1.topic_id)
     expect(tu.last_read_post_number).to eq(p2.post_number)
-    expect(tu.highest_seen_post_number).to eq(2)
 
   end
 
diff --git a/spec/requests/api/private_messages_spec.rb b/spec/requests/api/private_messages_spec.rb
index 11d1974472..9bb3f6bef3 100644
--- a/spec/requests/api/private_messages_spec.rb
+++ b/spec/requests/api/private_messages_spec.rb
@@ -64,8 +64,7 @@ describe 'private messages' do
                     archetype: { type: :string },
                     unseen: { type: :boolean },
                     last_read_post_number: { type: :integer },
-                    unread: { type: :integer },
-                    new_posts: { type: :integer },
+                    unread_posts: { type: :integer },
                     pinned: { type: :boolean },
                     unpinned: { type: :string, nullable: true },
                     visible: { type: :boolean },
@@ -174,8 +173,7 @@ describe 'private messages' do
                     archetype: { type: :string },
                     unseen: { type: :boolean },
                     last_read_post_number: { type: :integer },
-                    unread: { type: :integer },
-                    new_posts: { type: :integer },
+                    unread_posts: { type: :integer },
                     pinned: { type: :boolean },
                     unpinned: { type: :string, nullable: true },
                     visible: { type: :boolean },
diff --git a/spec/requests/api/tags_spec.rb b/spec/requests/api/tags_spec.rb
index 160100865d..47ec2cfbcd 100644
--- a/spec/requests/api/tags_spec.rb
+++ b/spec/requests/api/tags_spec.rb
@@ -277,8 +277,7 @@ describe 'tags' do
                     archetype: { type: :string },
                     unseen: { type: :boolean },
                     last_read_post_number: { type: :integer },
-                    unread: { type: :integer },
-                    new_posts: { type: :integer },
+                    unread_posts: { type: :integer },
                     pinned: { type: :boolean },
                     unpinned: { type: :string, nullable: true },
                     visible: { type: :boolean },
diff --git a/spec/requests/api/topics_spec.rb b/spec/requests/api/topics_spec.rb
index a2592cae03..ba67bc376f 100644
--- a/spec/requests/api/topics_spec.rb
+++ b/spec/requests/api/topics_spec.rb
@@ -225,8 +225,7 @@ describe 'topics' do
                 archetype: { type: :string },
                 unseen: { type: :boolean },
                 last_read_post_number: { type: :integer },
-                unread: { type: :integer },
-                new_posts: { type: :integer },
+                unread_posts: { type: :integer },
                 pinned: { type: :boolean },
                 unpinned: { type: :boolean },
                 visible: { type: :boolean },
@@ -603,8 +602,7 @@ describe 'topics' do
                     archetype: { type: :string },
                     unseen: { type: :boolean },
                     last_read_post_number: { type: :integer },
-                    unread: { type: :integer },
-                    new_posts: { type: :integer },
+                    unread_posts: { type: :integer },
                     pinned: { type: :boolean },
                     unpinned: { type: :string, nullable: true },
                     visible: { type: :boolean },
@@ -704,8 +702,7 @@ describe 'topics' do
                     archetype: { type: :string },
                     unseen: { type: :boolean },
                     last_read_post_number: { type: :integer },
-                    unread: { type: :integer },
-                    new_posts: { type: :integer },
+                    unread_posts: { type: :integer },
                     pinned: { type: :boolean },
                     unpinned: { type: :boolean },
                     visible: { type: :boolean },
@@ -807,8 +804,7 @@ describe 'topics' do
                     archetype: { type: :string },
                     unseen: { type: :boolean },
                     last_read_post_number: { type: :integer },
-                    unread: { type: :integer },
-                    new_posts: { type: :integer },
+                    unread_posts: { type: :integer },
                     pinned: { type: :boolean },
                     unpinned: { type: :boolean },
                     visible: { type: :boolean },
diff --git a/spec/requests/topics_controller_spec.rb b/spec/requests/topics_controller_spec.rb
index 444fc31afc..ccc4bf121c 100644
--- a/spec/requests/topics_controller_spec.rb
+++ b/spec/requests/topics_controller_spec.rb
@@ -1010,7 +1010,6 @@ RSpec.describe TopicsController do
 
         topic_user.update!(
           last_read_post_number: 2,
-          highest_seen_post_number: 2
         )
 
         # ensure we have 2 notifications
@@ -1036,7 +1035,7 @@ RSpec.describe TopicsController do
         expect(PostTiming.where(topic: topic, user: user, post_number: 2).exists?).to eq(false)
         expect(PostTiming.where(topic: topic, user: user, post_number: 1).exists?).to eq(true)
 
-        expect(TopicUser.where(topic: topic, user: user, last_read_post_number: 1, highest_seen_post_number: 1).exists?).to eq(true)
+        expect(TopicUser.where(topic: topic, user: user, last_read_post_number: 1).exists?).to eq(true)
 
         user.user_stat.reload
         expect(user.user_stat.first_unread_at).to eq_time(topic.updated_at)
@@ -1051,7 +1050,7 @@ RSpec.describe TopicsController do
         delete "/t/#{topic.id}/timings.json?last=1"
 
         expect(PostTiming.where(topic: topic, user: user, post_number: 1).exists?).to eq(false)
-        expect(TopicUser.where(topic: topic, user: user, last_read_post_number: nil, highest_seen_post_number: nil).exists?).to eq(true)
+        expect(TopicUser.where(topic: topic, user: user, last_read_post_number: nil).exists?).to eq(true)
       end
     end
 
diff --git a/spec/services/post_alerter_spec.rb b/spec/services/post_alerter_spec.rb
index 53c61f6b5c..a0969fab93 100644
--- a/spec/services/post_alerter_spec.rb
+++ b/spec/services/post_alerter_spec.rb
@@ -1259,7 +1259,13 @@ describe PostAlerter do
     fab!(:category) { Fabricate(:category) }
 
     it 'creates single edit notification when post is modified' do
-      TopicUser.create!(user_id: user.id, topic_id: topic.id, notification_level: TopicUser.notification_levels[:watching], highest_seen_post_number: post.post_number)
+      TopicUser.create!(
+        user_id: user.id,
+        topic_id: topic.id,
+        notification_level: TopicUser.notification_levels[:watching],
+        last_read_post_number: post.post_number
+      )
+
       PostRevisor.new(post).revise!(last_editor, tags: [tag.name])
       PostAlerter.new.notify_post_users(post, [])
       expect(Notification.count).to eq(1)
@@ -1280,7 +1286,7 @@ describe PostAlerter do
         category: category.id
       )
 
-      TopicUser.change(user, post.topic_id, highest_seen_post_number: post.post_number)
+      TopicUser.change(user, post.topic_id, last_read_post_number: post.post_number)
 
       # Manually run job after the user read the topic to simulate a slow
       # Sidekiq.