There is a little problem in version 188.8.131.52:
When there is unseen mail, iMapper does not count it correctly.
It gives a number which is 1 less than true.
This appears to lead to an
error in the IMAP command FETCH: invalid messageset.
I'm sorry for the delay. It's vacation season, so things are a little busy.
Anyhow, so far I haven't been able to reproduce the problem.