They use Office 365 and have always required phones to be enrolled
(giving their IT department full access) in order for email etc. to be
accessible. However, I used to be able to circumvent this by accessing
my Office 365 emails through IMAP.
You clearly don't respect your clients or value their business or the business relationship you have with ...
The original answer from 2011 is outdated.
Dovecot lifecycle announcement:
For any version before 2.2, we are not going to be providing any patches
or fixes. This has been the case before, but we are now officially
declaring them EOL.
I will still list all versions for reference. Sometimes admins have to run software they'd rather not run.