Group audio calls no more working on win 10 mobile

[anon(8057870)]

I used to recieve group skype audio calls on my lumia 920 with latest win 10 insider until a week back. Now it gives a message
Message from Skype

To join this call, these people need to go online or update Skype: Salil . Find out more at https://go.skype.com/groupupgrade

Any idea ?