underscore in LSA RM ID no longer accepted - impact on clients?

Lawson is working on a patch to eliminate the use of underscore in RM ID in LSA when we create a Lawson user id - even now it wont accept the underscore when you type it but you can copy and paste the ID's with underscore.

This is going to impact the customers who are using underscore(_) on their user id's. Does any one aware of this patch?

What would happen for the customers who already has such RM id's - which can either come from 8.x migration or created by process flow rm update node.

Also, Have you seen customers using underscore (_) on their RM ID's?

Thanks