diff --git a/app/actions/views/channel.js b/app/actions/views/channel.js
index f919e6c73..64b29a3c0 100644
--- a/app/actions/views/channel.js
+++ b/app/actions/views/channel.js
@@ -199,7 +199,7 @@ export function loadPostsIfNecessaryWithRetry(channelId) {
                 });
             }
         } else {
-            const {lastConnectAt} = state.websocket;
+            const lastConnectAt = state.websocket?.lastConnectAt || 0;
             const lastGetPosts = state.views.channel.lastGetPosts[channelId];
 
             let since;
diff --git a/app/actions/views/channel.test.js b/app/actions/views/channel.test.js
index 2b06a97d4..3775ad84b 100644
--- a/app/actions/views/channel.test.js
+++ b/app/actions/views/channel.test.js
@@ -4,7 +4,15 @@
 import configureStore from 'redux-mock-store';
 import thunk from 'redux-thunk';
 
-import {handleSelectChannelByName} from 'app/actions/views/channel';
+import initialState from 'app/initial_state';
+import testHelper from 'test/test_helper';
+
+import {
+    handleSelectChannelByName,
+    loadPostsIfNecessaryWithRetry,
+} from 'app/actions/views/channel';
+
+import postReducer from 'mattermost-redux/reducers/entities/posts';
 
 jest.mock('mattermost-redux/selectors/entities/channels', () => ({
     getChannel: () => ({data: 'received-channel-id'}),
@@ -19,6 +27,9 @@ describe('Actions.Views.Channel', () => {
 
     const MOCK_SELECT_CHANNEL_TYPE = 'MOCK_SELECT_CHANNEL_TYPE';
     const MOCK_RECEIVE_CHANNEL_TYPE = 'MOCK_RECEIVE_CHANNEL_TYPE';
+    const MOCK_RECEIVED_POSTS = 'RECEIVED_POSTS';
+    const MOCK_RECEIVED_POSTS_IN_CHANNEL = 'RECEIVED_POSTS_IN_CHANNEL';
+    const MOCK_RECEIVED_POSTS_SINCE = 'MOCK_RECEIVED_POSTS_SINCE';
 
     const actions = require('mattermost-redux/actions/channels');
     actions.getChannelByNameAndTeamName = jest.fn((teamName) => {
@@ -38,14 +49,51 @@ describe('Actions.Views.Channel', () => {
         type: MOCK_SELECT_CHANNEL_TYPE,
         data: 'selected-channel-id',
     });
+    const postActions = require('mattermost-redux/actions/posts');
+    postActions.getPostsSince = jest.fn(() => {
+        return {
+            type: MOCK_RECEIVED_POSTS_SINCE,
+            data: {
+                order: [],
+                posts: {},
+            },
+        };
+    });
 
+    postActions.getPosts = jest.fn((channelId) => {
+        const order = [];
+        const posts = {};
+
+        for (let i = 0; i < 60; i++) {
+            const p = testHelper.fakePost(channelId);
+            order.push(p.id);
+            posts[p.id] = p;
+        }
+
+        return {
+            type: MOCK_RECEIVED_POSTS,
+            data: {
+                order,
+                posts,
+            },
+        };
+    });
+
+    const postUtils = require('mattermost-redux/utils/post_utils');
+    postUtils.getLastCreateAt = jest.fn((array) => {
+        return array[0].create_at;
+    });
+
+    let nextPostState = {};
     const currentUserId = 'current-user-id';
     const currentChannelId = 'channel-id';
     const currentChannelName = 'channel-name';
     const currentTeamId = 'current-team-id';
     const currentTeamName = 'current-team-name';
     const storeObj = {
+        ...initialState,
         entities: {
+            ...initialState.entities,
             users: {
                 currentUserId,
             },
@@ -93,4 +141,84 @@ describe('Actions.Views.Channel', () => {
         const storeBatchActions = storeActions.some(({type}) => type === 'BATCHING_REDUCER.BATCH');
         expect(storeBatchActions).toBe(false);
     });
+
+    test('loadPostsIfNecessaryWithRetry for the first time', async () => {
+        store = mockStore(storeObj);
+
+        await store.dispatch(loadPostsIfNecessaryWithRetry(currentChannelId));
+        expect(postActions.getPosts).toBeCalled();
+
+        const storeActions = store.getActions();
+        const storeBatchActions = storeActions.filter(({type}) => type === 'BATCHING_REDUCER.BATCH');
+        const receivedPosts = storeActions.find(({type}) => type === MOCK_RECEIVED_POSTS);
+        const receivedPostsAtAction = storeBatchActions[0].payload.some((action) => action.type === 'RECEIVED_POSTS_FOR_CHANNEL_AT_TIME');
+
+        nextPostState = postReducer(store.getState().entities.posts, receivedPosts);
+        nextPostState = postReducer(nextPostState, {
+            type: MOCK_RECEIVED_POSTS_IN_CHANNEL,
+            channelId: currentChannelId,
+            data: receivedPosts.data,
+            recent: true,
+        });
+
+        expect(receivedPostsAtAction).toBe(true);
+    });
+
+    test('loadPostsIfNecessaryWithRetry get posts since', async () => {
+        store = mockStore({
+            ...storeObj,
+            entities: {
+                ...storeObj.entities,
+                posts: nextPostState,
+            },
+            views: {
+                ...storeObj.views,
+                channel: {
+                    ...storeObj.views.channel,
+                    lastGetPosts: {
+                        [currentChannelId]: Date.now(),
+                    },
+                },
+            },
+        });
+
+        await store.dispatch(loadPostsIfNecessaryWithRetry(currentChannelId));
+        const storeActions = store.getActions();
+        const receivedPostsSince = storeActions.find(({type}) => type === MOCK_RECEIVED_POSTS_SINCE);
+
+        expect(postUtils.getLastCreateAt).toBeCalled();
+        expect(postActions.getPostsSince).toHaveBeenCalledWith(currentChannelId, Object.values(store.getState().entities.posts.posts)[0].create_at);
+        expect(receivedPostsSince).not.toBe(null);
+    });
+
+    test('loadPostsIfNecessaryWithRetry get posts since the websocket reconnected', async () => {
+        const time = Date.now();
+        store = mockStore({
+            ...storeObj,
+            entities: {
+                ...storeObj.entities,
+                posts: nextPostState,
+            },
+            views: {
+                ...storeObj.views,
+                channel: {
+                    ...storeObj.views.channel,
+                    lastGetPosts: {
+                        [currentChannelId]: time,
+                    },
+                },
+            },
+            websocket: {
+                lastConnectAt: time + (1 * 60 * 1000),
+            },
+        });
+
+        await store.dispatch(loadPostsIfNecessaryWithRetry(currentChannelId));
+        const storeActions = store.getActions();
+        const receivedPostsSince = storeActions.find(({type}) => type === MOCK_RECEIVED_POSTS_SINCE);
+
+        expect(postUtils.getLastCreateAt).not.toBeCalled();
+        expect(postActions.getPostsSince).toHaveBeenCalledWith(currentChannelId, store.getState().views.channel.lastGetPosts[currentChannelId]);
+        expect(receivedPostsSince).not.toBe(null);
+    });
 });
diff --git a/test/test_helper.js b/test/test_helper.js
index c4624397f..8bfe368ff 100644
--- a/test/test_helper.js
+++ b/test/test_helper.js
@@ -5,7 +5,7 @@ import assert from 'assert';
 
 import Config from 'assets/config.json';
 
-import Client from 'mattermost-redux/client/client';
+import Client from 'mattermost-redux/client/client4';
 
 const PASSWORD = 'password1';
 
@@ -103,8 +103,13 @@ class TestHelper {
     };
 
     fakePost = (channelId) => {
+        const time = Date.now();
+
         return {
+            id: this.generateId(),
             channel_id: channelId,
+            create_at: time,
+            update_at: time,
             message: `Unit Test ${this.generateId()}`,
         };
     };