Cloud-based Message Recall in Exchange Online

sankalpa_69 >>however recall function on shared mailbox is still grid out?

Graying out the recall option is a function of the client (e.g. Outlook or Outlook on the web). I'm on the server-side (Transport) not client-side, but my understanding is that there are some shared mailbox scenarios where Outlook never supported recall (grayed it out), and those scenarios still aren't supported. Feel free to PM me your exact scenario (how shared mailbox set up, user scenario end-to-end including which client used) and I can coordinate with my colleagues on the client teams to determine the feasibility of future support for it. 

FWIW, the issue we recently fixed in December for shared mailboxes is for users who send as / FROM a shared mailbox, but the message is copied to *their* sent items folder not the shared mailbox's sent items. They could recall fine, but they could NOT view the recall report - now they can.

Hoegi71 >>. . .ALL emails (incl. internal emails) flow through the CodeTwo service and therefore all emails are classified as external.

We did a good bit of investigation/brainstorming on this over the last quarter and have plans to deploy an update to support this scenario hopefully by next summer.