Design theme files have been updated with a variety of style sheet and HTML changes.
During migration, all design theme files used by your application are replaced with new ones. This includes your applications’ CSS style sheet files. Any changes you have made to your applications’ design theme files will be lost.
Re-apply any changes you have made to your application’s design theme files and CSS style sheet files after your application is migrated to V4.1.
Version 4.1 Application Migration