The Sign-In control has been “localized”, with its various text strings moved to the language translation files (RESX files). There are new new design theme template files for the Sign In control.
During migration, new Sign In control files will replace the old ones in your application. The original safe code-behind file will be backed up and then deleted from your application.
If you have changed the original Sign In control’s HTML template files, your changes will be lost. You should re-apply your changes after your application is migrated to V4.0. Also, any code customizations made in the Sign In control’s code-behind fil will be lost. You should re-apply your changes after your application is migrated to V4.0.