diff --git a/www/checkup/main.js b/www/checkup/main.js
index fd0b41a27..d710747d7 100644
--- a/www/checkup/main.js
+++ b/www/checkup/main.js
@@ -363,7 +363,7 @@ define([
         });
     });
 
-    var sheetURL = '/common/onlyoffice/v4/web-apps/apps/spreadsheeteditor/main/index.html';
+    var sheetURL = '/common/onlyoffice/v5/web-apps/apps/spreadsheeteditor/main/index.html';
 
     assert(function (cb, msg) {
         msg.innerText = "Missing HTTP headers required for .xlsx export from sheets. ";
@@ -671,7 +671,7 @@ define([
     });
 
     assert(function (cb, msg) {
-        var url = '/common/onlyoffice/v4/web-apps/apps/spreadsheeteditor/main/index.html';
+        var url = '/common/onlyoffice/v5/web-apps/apps/spreadsheeteditor/main/index.html';
         msg.appendChild(CSP_WARNING(url));
         deferredPostMessage({
             command: 'GET_HEADER',
diff --git a/www/common/onlyoffice/inner.js b/www/common/onlyoffice/inner.js
index 5684a1dd8..db4f98f52 100644
--- a/www/common/onlyoffice/inner.js
+++ b/www/common/onlyoffice/inner.js
@@ -2856,8 +2856,8 @@ Uncaught TypeError: Cannot read property 'calculatedType' of null
                     }
                     readOnly = true;
                 }
-            } else if (content && content.version <= 3) { // V2 or V3
-                version = 'v2b/';
+            } else if (content && content.version <= 4) { // V2 or V3
+                version = content.version <= 3 ? 'v2b/' : 'v4/';
                 APP.migrate = true;
                 // Registedred ~~users~~ editors can start the migration
                 if (common.isLoggedIn() && !readOnly) {
diff --git a/www/common/outer/x2t.js b/www/common/outer/x2t.js
index 76dcd2f75..494c25a62 100644
--- a/www/common/outer/x2t.js
+++ b/www/common/outer/x2t.js
@@ -5,7 +5,7 @@ define([
 ], function (ApiConfig, nThen, Util) {
     var X2T = {};
 
-    var CURRENT_VERSION = X2T.CURRENT_VERSION = 'v4';
+    var CURRENT_VERSION = X2T.CURRENT_VERSION = 'v5';
     var debug = function (str) {
         if (localStorage.CryptPad_dev !== "1") { return; }
         console.debug(str);
diff --git a/www/convert/inner.js b/www/convert/inner.js
index c8b2cdd71..062d37592 100644
--- a/www/convert/inner.js
+++ b/www/convert/inner.js
@@ -10,6 +10,7 @@ define([
     '/common/common-interface.js',
     '/common/common-util.js',
     '/common/outer/worker-channel.js',
+    '/common/outer/x2t.js',
     '/bower_components/file-saver/FileSaver.min.js',
     'css!/bower_components/bootstrap/dist/css/bootstrap.min.css',
     'css!/bower_components/components-font-awesome/css/font-awesome.min.css',
@@ -25,10 +26,12 @@ define([
     Messages,
     UI,
     Util,
-    Channel
+    Channel,
+    X2T
     )
 {
     var APP = window.APP = {};
+    var CURRENT_VERSION = X2T.CURRENT_VERSION;
 
     var common;
     var sFrameChan;
@@ -111,7 +114,7 @@ define([
     var loadOO = function (blob, type, name, cb) {
         var s = h('script', {
             type:'text/javascript',
-            src: '/common/onlyoffice/v4/web-apps/apps/api/documents/api.js'
+            src: '/common/onlyoffice/'+CURRENT_VERSION+'/web-apps/apps/api/documents/api.js'
         });
         var file = getFileType(type);
         APP.$rightside.append(s);