As announced at Microsoft Ignite 2020, support for plus addressing is now available in Exchange Online. Thanks to our UserVoice site, this feature was identified as the number 1 request for Exchange ...
Updated Oct 27, 2020
Version 3.0
Blog Post
SeanMSFT
Microsoft
Microsoftajc196 Thank you for circling back with the answers you found.
Support for Groups and DL is being added and should be available in December.
Andres-Bohren The time that the setting takes to permeate through the service differs but it should be in the region of hours, not days. If it is still not working, I would advise you to contact support to help diagnose the issue.
SyPatWork Kam We are updating the documentation to be more specific about the expected behaviour. If Exchange Online can resolve the existing address with the plus, then it will be delivered as normal. The problem comes in for mailboxes on-premises that Exchange Online does not know about and message are being blindly routing messages via connector to the mailbox. In such a case, we will assume that the message is a plus address and strip out the plus and tag and deliver it to the parsed address.
DanielNiccoli Custom characters for sub-addressing is not something we have any intention to implement in the foreseeable future.