I agree that there are better ways to keep things documented. Any fix communicated over email might as well include (or even better only include) a link to the actual documentation wherever it actually belongs, but that's a terrible reason to abandon IMAP and force people to use Outlook. It's so terrible a reason it's hard to imagine that was their only one. I imagine most companies are more worried about leaks or compromised email accounts than about documentation ending up saved in email only.