Ability to have versions 28.0 and 28.1 on the same machine.

As accountants we are linked through RDA to many clients. One client ( A group of 7 companies) has upgraded to 28.1 with out discussing with us. This means that either the staff have to upgrade to use that version and not access the others or they cant access that large client but can continue supporting the other clients. This is extremely unhelpful as we now have to go round all clients and help them upgrade.