Microsoft.Exchange.Clients.Common\Clients\Common\Canary15.cs
Changes in hash implementation, don’t know what it’s for
Microsoft.Exchange.Data.ApplicationLogic\Exchange\Data\ApplicationLogic\Cafe\BackEndServer.cs
Add this

Microsoft.Exchange.Data.ApplicationLogic\Exchange\Data\ApplicationLogic\MailboxFileStore.cs

Microsoft.Exchange.FrontEndHttpProxy\HttpProxy\BEResourceRequestHandler.cs
Add this

Microsoft.Exchange.FrontEndHttpProxy\HttpProxy\ProxyRequestHandler.cs
Verify hostname and proxyKerberosAuthentication.

The uri variable above is described as
Uri uri = this.GetTargetBackEndServerUrl();
Microsoft.Exchange.FrontEndHttpProxy\HttpProxy\ServerInfoAnchorMailbox.cs
Add check

Microsoft.Exchange.Management\Exchange\Management\Common\CmdletRunner.cs
Microsoft.Exchange.Management\Exchange\Management\Common\CmdletValidator.cs