Skip migration if it's not needed

www/common/onlyoffice/inner.js

@@ -2858,6 +2858,14 @@ Uncaught TypeError: Cannot read property 'calculatedType' of null
                 }
             } else if (content && content.version <= 4) { // V2 or V3
                 version = content.version <= 3 ? 'v2b/' : 'v4/';
+                var skip = false;
+                if (content.version === 4 && NEW_VERSION === 5) {
+                    // Skip if there is no chart in the document
+                    skip = !getEditor().GetDocument().GetAllCharts().length;
+                }
+                if (skip) {
+                    content.version = NEW_VERSION;
+                } else {
                     APP.migrate = true;
                     // Registedred ~~users~~ editors can start the migration
                     if (common.isLoggedIn() && !readOnly) {
@@ -2873,6 +2881,7 @@ Uncaught TypeError: Cannot read property 'calculatedType' of null
                         readOnly = true;
                     }
                 }
+            }
             // NOTE: don't forget to also update the version in 'EV_OOIFRAME_REFRESH'
 
             // If the sheet is locked by an offline user, remove it