diff --git a/apps/presentationeditor/main/app/controller/LeftMenu.js b/apps/presentationeditor/main/app/controller/LeftMenu.js
index 5c847f570..c0ce2d5b1 100644
--- a/apps/presentationeditor/main/app/controller/LeftMenu.js
+++ b/apps/presentationeditor/main/app/controller/LeftMenu.js
@@ -349,6 +349,10 @@ define([
                     Common.Utils.InternalSettings.set("pe-settings-coauthmode", fast_coauth);
                     this.api.asc_SetFastCollaborative(fast_coauth);
                 }
+            } else if (!this.mode.isEdit && !this.mode.isRestrictedEdit && !this.mode.isOffline && this.mode.canChangeCoAuthoring) { // viewer
+                fast_coauth = Common.localStorage.getBool("pe-settings-view-coauthmode", false);
+                Common.Utils.InternalSettings.set("pe-settings-coauthmode", fast_coauth);
+                this.api.asc_SetFastCollaborative(fast_coauth);
             }
             /** coauthoring end **/
 
diff --git a/apps/presentationeditor/main/app/controller/Main.js b/apps/presentationeditor/main/app/controller/Main.js
index eb06f07ec..56745bc62 100644
--- a/apps/presentationeditor/main/app/controller/Main.js
+++ b/apps/presentationeditor/main/app/controller/Main.js
@@ -1168,7 +1168,9 @@ define([
                 this.appOptions.canBrandingExt && this.editorConfig.customization && Common.UI.LayoutManager.init(this.editorConfig.customization.layout);
                 this.appOptions.canBrandingExt && this.editorConfig.customization && Common.UI.FeaturesManager.init(this.editorConfig.customization.features);
 
-                this.appOptions.canChangeCoAuthoring = this.appOptions.isEdit && this.appOptions.canCoAuthoring && !(typeof this.editorConfig.coEditing == 'object' && this.editorConfig.coEditing.change===false);
+                // change = true by default in editor, change = false by default in viewer
+                this.appOptions.canChangeCoAuthoring = this.appOptions.isEdit && this.appOptions.canCoAuthoring && !(typeof this.editorConfig.coEditing == 'object' && this.editorConfig.coEditing.change===false) ||
+                                                    !this.appOptions.isEdit && !this.appOptions.isRestrictedEdit && (typeof this.editorConfig.coEditing == 'object' && this.editorConfig.coEditing.change===true) ;
 
                 this.loadCoAuthSettings();
                 this.applyModeCommonElements();
@@ -1210,6 +1212,16 @@ define([
                     fastCoauth = (value===null || parseInt(value) == 1);
                 } else if (!this.appOptions.isEdit && this.appOptions.isRestrictedEdit) {
                     fastCoauth = true;
+                } else if (!this.appOptions.isEdit && !this.appOptions.isRestrictedEdit && !this.appOptions.isOffline) { // viewer
+                    if (!this.appOptions.canChangeCoAuthoring) { //can't change co-auth. mode. Use coEditing.mode or 'strict' by default
+                        value = this.editorConfig.coEditing && this.editorConfig.coEditing.mode==='fast' ? 1 : 0;
+                    } else {
+                        value = Common.localStorage.getItem("pe-settings-view-coauthmode");
+                        if (value===null) {
+                            value = this.editorConfig.coEditing && this.editorConfig.coEditing.mode==='fast' ? 1 : 0;
+                        }
+                    }
+                    fastCoauth = (parseInt(value) == 1);
                 } else {
                     fastCoauth = false;
                     autosave = 0;
diff --git a/apps/presentationeditor/main/app/view/FileMenuPanels.js b/apps/presentationeditor/main/app/view/FileMenuPanels.js
index ad2f79edd..33e2e3374 100644
--- a/apps/presentationeditor/main/app/view/FileMenuPanels.js
+++ b/apps/presentationeditor/main/app/view/FileMenuPanels.js
@@ -231,7 +231,11 @@ define([
                         '<div><div id="fms-cmb-coauth-mode" style="display: inline-block; margin-right: 15px;vertical-align: middle;"></div>',
                         '<label id="fms-lbl-coauth-mode" style="vertical-align: middle;"><%= scope.strCoAuthModeDescFast %></label></div></td>',
                 '</tr>','<tr class="divider coauth changes"></tr>',
-                /** coauthoring end **/
+                '<tr class="live-viewer">',
+                    '<td class="left"><label><%= scope.txtLiveViewer %></label></td>',
+                    '<td class="right"><div id="fms-chb-live-viewer"></div></td>',
+                '</tr>','<tr class="divider live-viewer"></tr>',
+            /** coauthoring end **/
                 '<tr class="themes">',
                     '<td class="left"><label><%= scope.strTheme %></label></td>',
                     '<td class="right"><span id="fms-cmb-theme"></span></td>',
@@ -351,6 +355,14 @@ define([
             this.lblCoAuthMode = $markup.findById('#fms-lbl-coauth-mode');
             /** coauthoring end **/
 
+            this.chLiveViewer = new Common.UI.CheckBox({
+                el: $markup.findById('#fms-chb-live-viewer'),
+                labelText: this.strShowOthersChanges,
+                dataHint: '2',
+                dataHintDirection: 'left',
+                dataHintOffset: 'small'
+            });
+
             this.chAutosave = new Common.UI.CheckBox({
                 el: $markup.findById('#fms-chb-autosave'),
                 labelText: this.strAutosave,
@@ -526,6 +538,7 @@ define([
             /** coauthoring begin **/
             $('tr.coauth.changes', this.el)[mode.isEdit && !mode.isOffline && mode.canCoAuthoring && mode.canChangeCoAuthoring ? 'show' : 'hide']();
             /** coauthoring end **/
+            $('tr.live-viewer', this.el)[!mode.isEdit && !mode.isRestrictedEdit && !mode.isOffline && mode.canChangeCoAuthoring ? 'show' : 'hide']();
             $('tr.macros', this.el)[(mode.customization && mode.customization.macros===false) ? 'hide' : 'show']();
             $('tr.spellcheck', this.el)[mode.isEdit && Common.UI.FeaturesManager.canChange('spellcheck') ? 'show' : 'hide']();
 
@@ -556,6 +569,7 @@ define([
             this.cmbCoAuthMode.setValue(item ? item.get('value') : 1);
             this.lblCoAuthMode.text(item ? item.get('descValue') : this.strCoAuthModeDescFast);
             /** coauthoring end **/
+            this.chLiveViewer.setValue(Common.Utils.InternalSettings.get("pe-settings-coauthmode"));
 
             value = Common.Utils.InternalSettings.get("pe-settings-fontrender");
             item = this.cmbFontRender.store.findWhere({value: parseInt(value)});
@@ -609,14 +623,17 @@ define([
             /** coauthoring begin **/
             if (this.mode.isEdit && !this.mode.isOffline && this.mode.canCoAuthoring && this.mode.canChangeCoAuthoring) {
                 Common.localStorage.setItem("pe-settings-coauthmode", this.cmbCoAuthMode.getValue());
+            } else if (!this.mode.isEdit && !this.mode.isRestrictedEdit && !this.mode.isOffline && this.mode.canChangeCoAuthoring) { // viewer
+                Common.localStorage.setItem("pe-settings-view-coauthmode", this.chLiveViewer.isChecked() ? 1 : 0);
             }
             /** coauthoring end **/
             Common.localStorage.setItem("pe-settings-fontrender", this.cmbFontRender.getValue());
             var item = this.cmbFontRender.store.findWhere({value: 'custom'});
             Common.localStorage.setItem("pe-settings-cachemode", item && !item.get('checked') ? 0 : 1);
             Common.localStorage.setItem("pe-settings-unit", this.cmbUnit.getValue());
-            if (this.mode.canChangeCoAuthoring || !Common.Utils.InternalSettings.get("pe-settings-coauthmode"))
+            if (this.mode.isEdit && (this.mode.canChangeCoAuthoring || !Common.Utils.InternalSettings.get("pe-settings-coauthmode")))
                 Common.localStorage.setItem("pe-settings-autosave", this.chAutosave.isChecked() ? 1 : 0);
+
             if (this.mode.canForcesave)
                 Common.localStorage.setItem("pe-settings-forcesave", this.chForcesave.isChecked() ? 1 : 0);
             Common.Utils.InternalSettings.set("pe-settings-showsnaplines", this.chAlignGuides.isChecked());
@@ -702,7 +719,9 @@ define([
         strTheme: 'Theme',
         txtThemeLight: 'Light',
         txtThemeDark: 'Dark',
-        txtAutoCorrect: 'AutoCorrect options...'
+        txtAutoCorrect: 'AutoCorrect options...',
+        strShowOthersChanges: 'Show changes from other users',
+        txtLiveViewer: 'Real-time Collaboration Changes'
     }, PE.Views.FileMenuPanels.Settings || {}));
 
     PE.Views.FileMenuPanels.RecentFiles = Common.UI.BaseView.extend({
diff --git a/apps/spreadsheeteditor/main/app/controller/LeftMenu.js b/apps/spreadsheeteditor/main/app/controller/LeftMenu.js
index 1db7baf2f..38260ebdf 100644
--- a/apps/spreadsheeteditor/main/app/controller/LeftMenu.js
+++ b/apps/spreadsheeteditor/main/app/controller/LeftMenu.js
@@ -449,6 +449,10 @@ define([
                     Common.Utils.InternalSettings.set("sse-settings-coauthmode", fast_coauth);
                     this.api.asc_SetFastCollaborative(fast_coauth);
                 }
+            } else if (!this.mode.isEdit && !this.mode.isRestrictedEdit && !this.mode.isOffline && this.mode.canChangeCoAuthoring) { // viewer
+                fast_coauth = Common.localStorage.getBool("sse-settings-view-coauthmode", false);
+                Common.Utils.InternalSettings.set("sse-settings-coauthmode", fast_coauth);
+                this.api.asc_SetFastCollaborative(fast_coauth);
             }
             /** coauthoring end **/
 
diff --git a/apps/spreadsheeteditor/main/app/controller/Main.js b/apps/spreadsheeteditor/main/app/controller/Main.js
index 7bb67714a..6496c34be 100644
--- a/apps/spreadsheeteditor/main/app/controller/Main.js
+++ b/apps/spreadsheeteditor/main/app/controller/Main.js
@@ -1265,8 +1265,10 @@ define([
                 this.appOptions.canHelp        = !((typeof (this.editorConfig.customization) == 'object') && this.editorConfig.customization.help===false);
                 this.appOptions.isRestrictedEdit = !this.appOptions.isEdit && this.appOptions.canComments;
 
+                // change = true by default in editor, change = false by default in viewer
                 this.appOptions.canChangeCoAuthoring = this.appOptions.isEdit && !(this.appOptions.isEditDiagram || this.appOptions.isEditMailMerge) && this.appOptions.canCoAuthoring &&
-                                                        !(typeof this.editorConfig.coEditing == 'object' && this.editorConfig.coEditing.change===false);
+                                                        !(typeof this.editorConfig.coEditing == 'object' && this.editorConfig.coEditing.change===false) ||
+                                                        !this.appOptions.isEdit && !this.appOptions.isRestrictedEdit && (typeof this.editorConfig.coEditing == 'object' && this.editorConfig.coEditing.change===true) ;
 
                 if (!this.appOptions.isEditDiagram && !this.appOptions.isEditMailMerge) {
                     this.appOptions.canBrandingExt = params.asc_getCanBranding() && (typeof this.editorConfig.customization == 'object' || this.editorConfig.plugins);
@@ -1323,6 +1325,16 @@ define([
                     fastCoauth = (value===null || parseInt(value) == 1);
                 } else if (!this.appOptions.isEdit && this.appOptions.isRestrictedEdit) {
                     fastCoauth = true;
+                }  else if (!this.appOptions.isEdit && !this.appOptions.isRestrictedEdit && !this.appOptions.isOffline) { // viewer
+                    if (!this.appOptions.canChangeCoAuthoring) { //can't change co-auth. mode. Use coEditing.mode or 'strict' by default
+                        value = this.editorConfig.coEditing && this.editorConfig.coEditing.mode==='fast' ? 1 : 0;
+                    } else {
+                        value = Common.localStorage.getItem("sse-settings-view-coauthmode");
+                        if (value===null) {
+                            value = this.editorConfig.coEditing && this.editorConfig.coEditing.mode==='fast' ? 1 : 0;
+                        }
+                    }
+                    fastCoauth = (parseInt(value) == 1);
                 } else {
                     fastCoauth = false;
                     autosave = 0;
diff --git a/apps/spreadsheeteditor/main/app/view/FileMenuPanels.js b/apps/spreadsheeteditor/main/app/view/FileMenuPanels.js
index 15f1ebc11..2ab843e23 100644
--- a/apps/spreadsheeteditor/main/app/view/FileMenuPanels.js
+++ b/apps/spreadsheeteditor/main/app/view/FileMenuPanels.js
@@ -312,6 +312,10 @@ define([
                         '<div><div id="fms-cmb-coauth-mode" style="display: inline-block; margin-right: 15px;vertical-align: middle;"></div>',
                         '<label id="fms-lbl-coauth-mode" style="vertical-align: middle;"><%= scope.strCoAuthModeDescFast %></label></div></td>',
                 '</tr>','<tr class="divider coauth changes"></tr>',
+                '<tr class="live-viewer">',
+                    '<td class="left"><label><%= scope.txtLiveViewer %></label></td>',
+                    '<td class="right"><div id="fms-chb-live-viewer"></div></td>',
+                '</tr>','<tr class="divider live-viewer"></tr>',
                 /** coauthoring end **/
                 '<tr class="themes">',
                     '<td class="left"><label><%= scope.strTheme %></label></td>',
@@ -438,6 +442,14 @@ define([
             this.lblCoAuthMode = $markup.findById('#fms-lbl-coauth-mode');
             /** coauthoring end **/
 
+            this.chLiveViewer = new Common.UI.CheckBox({
+                el: $markup.findById('#fms-chb-live-viewer'),
+                labelText: this.strShowOthersChanges,
+                dataHint: '2',
+                dataHintDirection: 'left',
+                dataHintOffset: 'small'
+            });
+
             this.cmbZoom = new Common.UI.ComboBox({
                 el          : $markup.findById('#fms-cmb-zoom'),
                 style       : 'width: 160px;',
@@ -756,6 +768,7 @@ define([
             $('tr.forcesave', this.el)[mode.canForcesave ? 'show' : 'hide']();
             $('tr.comments', this.el)[mode.canCoAuthoring ? 'show' : 'hide']();
             $('tr.coauth.changes', this.el)[mode.isEdit && !mode.isOffline && mode.canCoAuthoring && mode.canChangeCoAuthoring ? 'show' : 'hide']();
+            $('tr.live-viewer', this.el)[!mode.isEdit && !mode.isRestrictedEdit && !mode.isOffline && mode.canChangeCoAuthoring ? 'show' : 'hide']();
             $('tr.macros', this.el)[(mode.customization && mode.customization.macros===false) ? 'hide' : 'show']();
 
             if ( !Common.UI.Themes.available() ) {
@@ -783,6 +796,7 @@ define([
             this.cmbCoAuthMode.setValue(item ? item.get('value') : 1);
             this.lblCoAuthMode.text(item ? item.get('descValue') : this.strCoAuthModeDescFast);
             /** coauthoring end **/
+            this.chLiveViewer.setValue(Common.Utils.InternalSettings.get("sse-settings-coauthmode"));
 
             value = Common.Utils.InternalSettings.get("sse-settings-fontrender");
             item = this.cmbFontRender.store.findWhere({value: parseInt(value)});
@@ -873,13 +887,16 @@ define([
             Common.localStorage.setItem("sse-settings-resolvedcomment", this.chResolvedComment.isChecked() ? 1 : 0);
             if (this.mode.isEdit && !this.mode.isOffline && this.mode.canCoAuthoring && this.mode.canChangeCoAuthoring)
                 Common.localStorage.setItem("sse-settings-coauthmode", this.cmbCoAuthMode.getValue());
+            else if (!this.mode.isEdit && !this.mode.isRestrictedEdit && !this.mode.isOffline && this.mode.canChangeCoAuthoring) { // viewer
+                Common.localStorage.setItem("sse-settings-view-coauthmode", this.chLiveViewer.isChecked() ? 1 : 0);
+            }
             /** coauthoring end **/
             Common.localStorage.setItem("sse-settings-r1c1", this.chR1C1Style.isChecked() ? 1 : 0);
             Common.localStorage.setItem("sse-settings-fontrender", this.cmbFontRender.getValue());
             var item = this.cmbFontRender.store.findWhere({value: 'custom'});
             Common.localStorage.setItem("sse-settings-cachemode", item && !item.get('checked') ? 0 : 1);
             Common.localStorage.setItem("sse-settings-unit", this.cmbUnit.getValue());
-            if (this.mode.canChangeCoAuthoring || !Common.Utils.InternalSettings.get("sse-settings-coauthmode"))
+            if (this.mode.isEdit && (this.mode.canChangeCoAuthoring || !Common.Utils.InternalSettings.get("sse-settings-coauthmode")))
                 Common.localStorage.setItem("sse-settings-autosave", this.chAutosave.isChecked() ? 1 : 0);
             if (this.mode.canForcesave)
                 Common.localStorage.setItem("sse-settings-forcesave", this.chForcesave.isChecked() ? 1 : 0);
@@ -1052,7 +1069,9 @@ define([
         txtExamplePt: 'SOMA; MÍNIMO; MÁXIMO; CONTAR',
         txtExamplePtbr: 'SOMA; MÍNIMO; MÁXIMO; CONT.NÚM',
         txtExampleSv: 'SUMMA; MIN; MAX; ANTAL',
-        txtExampleTr: 'TOPLA; MİN; MAK; BAĞ_DEĞ_SAY'
+        txtExampleTr: 'TOPLA; MİN; MAK; BAĞ_DEĞ_SAY',
+        strShowOthersChanges: 'Show changes from other users',
+        txtLiveViewer: 'Real-time Collaboration Changes'
 
 }, SSE.Views.FileMenuPanels.MainSettingsGeneral || {}));