We have made the jump to 2.22, we have had some problems, but they seem to be resolved after following article 1793 on how to reset ActivInspire back to default.
One user is still experiencing issues, even after following article 1793 but I have yet to troubleshoot further, reported the crashing this morning.
I hope to report back with my findings soon, but I suggest if upgrading to 2.22, follow article 1793, it has solved MANY issues so far.