Do we know when? I was going to update, but will wait!
I assume that going from v20 to v21 on an XP system is still a good thing to do.
There is no problem upgrading now. The issue noted here is just a prompt that pops up when you log into your Identity Safe. As long as you read carefully and choose the right option, it does not cause any problem.
As to when the fix will be ready, the only answer you can get is 'When it's ready".
Any change to the code needs to be thoroughly tested to ensure it does not cause more problems than it fixes.