How can I compare Draft changes in Project Pro in Server Remote Event Handler with current Draft ver

If I change Draft version in Project Pro, how can I compare Draft changes by Project Pro in Server Remote Event Handler with current Draft ver?

IProjectEventReceiverRemote.OnUpdatingPwaProjectRemote

IProjectEventReceiverRemote.OnUpdatingScheduledProjectRemote
ProjectPreEventArgs IProjectEventReceiverRemote.OnUpdatingRemote

Or it's possible only in Project Pro Add-in?

BR, Vasily