The Crypto.cs (.vb) file has been updated with an enhanced encryption feature.
During migration, the Crypto.cs (.vb) file in your application is replaced with an updated file. Any changes you have made to this file will be lost. This file is located in:
...\<Application Folder>\App_Code\Shared\Crypto.cs (.vb)
After migration, re-apply any changes you may have made to the original Crypto.cs (.vb) file to the new file in your application.
Version 5.1 Application Migration