diff --git a/src/lib/extensions.js b/src/lib/extensions.js
index 75961e8dc..e6556dc6b 100644
--- a/src/lib/extensions.js
+++ b/src/lib/extensions.js
@@ -56,6 +56,7 @@ export const CODE_EXTENSIONS = [
 export const EXCEL_EXTENSIONS = ['xls', 'xlsm', 'xlsx'];
 export const EXCLUDED_EXTENSIONS = EXCEL_EXTENSIONS.concat(['numbers']);
 export const INDESIGN_EXTENSIONS = ['indb', 'indd', 'indl', 'indt', 'idml', 'inx', 'pmd'];
+export const OFFICE_ONLINE_EXTENSIONS = ['xlsx', 'xlsm', 'xlsb'];
 
 export const DOCUMENT_EXTENSIONS = CODE_EXTENSIONS.concat(NON_CODE_EXTENSIONS)
     .concat(HTML_EXTENSIONS)
diff --git a/src/lib/viewers/doc/DocumentViewer.js b/src/lib/viewers/doc/DocumentViewer.js
index 503fa9181..02a0b1edb 100644
--- a/src/lib/viewers/doc/DocumentViewer.js
+++ b/src/lib/viewers/doc/DocumentViewer.js
@@ -2,7 +2,7 @@ import Browser from '../../Browser';
 import DocBaseViewer from './DocBaseViewer';
 import DocPreloader from './DocPreloader';
 import fullscreen from '../../Fullscreen';
-import { EXCEL_EXTENSIONS } from '../../extensions';
+import { OFFICE_ONLINE_EXTENSIONS } from '../../extensions';
 import './Document.scss';
 
 class DocumentViewer extends DocBaseViewer {
@@ -42,9 +42,9 @@ class DocumentViewer extends DocBaseViewer {
         super.load();
 
         const { extension } = this.options.file;
-        const isExcelExtension = EXCEL_EXTENSIONS.includes(extension);
+        const isOfficeOnlineExtension = OFFICE_ONLINE_EXTENSIONS.includes(extension);
 
-        if (isExcelExtension && Browser.isIE()) {
+        if (isOfficeOnlineExtension && Browser.isIE()) {
             this.options.ui.showNotification(__('error_internet_explorer_office_online'), null, true);
         }
     }
diff --git a/src/lib/viewers/doc/__tests__/DocumentViewer-test.js b/src/lib/viewers/doc/__tests__/DocumentViewer-test.js
index b82a31c0e..550707e6c 100644
--- a/src/lib/viewers/doc/__tests__/DocumentViewer-test.js
+++ b/src/lib/viewers/doc/__tests__/DocumentViewer-test.js
@@ -6,6 +6,7 @@ import DocBaseViewer from '../DocBaseViewer';
 import BaseViewer from '../../BaseViewer';
 import DocPreloader from '../DocPreloader';
 import fullscreen from '../../../Fullscreen';
+import { OFFICE_ONLINE_EXTENSIONS } from '../../../extensions';
 
 let containerEl;
 let doc;
@@ -107,7 +108,7 @@ describe('lib/viewers/doc/DocumentViewer', () => {
             Object.defineProperty(DocBaseViewer.prototype, 'load', { value: docBaseLoadFunc });
         });
 
-        test.each(['xls', 'xlsm', 'xlsx'])(
+        test.each(OFFICE_ONLINE_EXTENSIONS)(
             'should show notification if file has excel extension %s and is internet explorer',
             extension => {
                 const showNotification = jest.fn();
@@ -121,7 +122,7 @@ describe('lib/viewers/doc/DocumentViewer', () => {
             },
         );
 
-        test.each(['xls', 'xlsm', 'xlsx'])(
+        test.each(OFFICE_ONLINE_EXTENSIONS)(
             'should not show notification if file has excel extension %s but is not internet explorer',
             extension => {
                 const showNotification = jest.fn();
diff --git a/src/lib/viewers/office/OfficeLoader.js b/src/lib/viewers/office/OfficeLoader.js
index 93dd3dc83..4b186225b 100644
--- a/src/lib/viewers/office/OfficeLoader.js
+++ b/src/lib/viewers/office/OfficeLoader.js
@@ -3,6 +3,7 @@ import AssetLoader from '../AssetLoader';
 import Browser from '../../Browser';
 import OfficeViewer from './OfficeViewer';
 import { checkPermission } from '../../file';
+import { OFFICE_ONLINE_EXTENSIONS } from '../../extensions';
 import { ORIGINAL_REP_NAME, PERMISSION_DOWNLOAD } from '../../constants';
 
 const FIVE_MB = 5242880;
@@ -14,7 +15,7 @@ const VIEWERS = [
         NAME: 'Office',
         CONSTRUCTOR: OfficeViewer,
         REP: ORIGINAL_REP_NAME,
-        EXT: ['xlsx', 'xlsm', 'xlsb'],
+        EXT: OFFICE_ONLINE_EXTENSIONS,
     },
 ];