Can't switch sides with partner version 14

Can anyone help with that persistent problem we're having with TeamViewer version 14. The only reason we upgraded from 13 to 14 (and switched to a subscription) was because the sales bumph said “say bye bye to backward compatibility issues” when changing sides with partners. However, we still have the problem on an almost daily basis. We run training webinars which require us to change sides regularly during sessions (both remote one-to-ones and group meetings) and the sessions are ruined when we get the dreaded “can't change sides with partner because they are running an older version of TeamViewer”.  Can somebody tell me please how to solve this problem? Or should we just look for a different supplier? The last time I inquired from support I was told to change the text in the meeting invitation link from V13 to V14 and this would work but it simply doesn’t.

I would be very grateful for any help with this issue.

Kind regards,