Just thought I'd let anyone who is interested that you do not need any additional license to change from a Minet to Sip softphone under 5.1
If you read the relase info, it implies that you need a free part number 54005889. I'm awaiting clarification, but I think scenario 3 should have included the mobile license. It's another I Miteled ya one thing but I should have Miteled ya another :-)