What I want people here to stop claiming is that Outlook "doesn't work/doesn't work well" with IMAP. It does, and always has.
I am not discussing business grade versus residential grade. We all know that most large entities have used MS-Exchange for years if not decades.
I'll maintain that Outlook does "not" work as well with IMAP as it does with its native Exchange support.
First..I'll acknowledge that IMAP is widespread, widely used, and will continue to be widely used for quite some time. It has a large market share. It came out before POP3....it lost market share to POP3....and then it regained market share as the limitations of POP3 quickly encouraged its demise in the early days of broadband.
And I'll acknowledge that it's OK for residential users. Realizing some limitations. But I don't work on residential users, don't want to. So those limitations it has...don't cause me any loss of sleep.
For business email...are where its limitations really surface and get many spotlights pointed on it. Many of which I noted above in my prior reply. Those aren't my opinion..they are factual limitations..in the business environment. Once one gets used to "all features working" of an Exchange environment...the limitations of IMAP combined with Outlook...are indeed...limitations...thus the clear and true statement..."doesn't work well". (refer to my list again in prior reply).
*Outlook doesn't work well with large mailboxes on IMAP services. It blows up. This is a limitation for a business. The opinions or preferences of some IT people to "not allow large mailboxes" isn't the debate, that's just an opinion. The facts are...Outlook will get cranky with mailboxes on IMAP once they reach around 20 or 25 gigs or more. Outlook works GREAT with mailboxes well beyond that...up to 100 gigs....if on Exchange. IMAP..does not. There is one limitation.
*Another limitation of IMAP....address books with Outlook Classic...."on this device only". Because it's stored in a local file, not in the mailbox...Exchange keeps it in the mailbox...so when doing computer migrations...or..an end user has multiple devices...each one is like a separate island. Brings back the days of POP3. Say a computers hard drive blows up...where did my address book go? If on Exchange..it's nice and safe. Stays with your account for the life on your account, because it's stored in the mailbox...thus equally accessible from all/any devices you have.
*Calendar..same as address book
*Signatures...same as address book
*Ability to send and receive large email attachments...which..a business should be able to do. Yes other online web based file sharing platforms are around ...but still for a business the need to send and/or receive file sizes larger than 25 megs is very common...
And security wise, I cannot lock down and secure a businesses email platform with any IMAP based email....as I can with Microsoft 365 Business Premium. ...and yes that's a different topic so I won't derail down that road...