Licensing Need in O365 for email retention

[BFMC-SysAdmin1775]

Hello Everyone,  just a quick question as I seem to be finding conflicting information.  What I am trying to do is when our company has a term employee we want to keep their e-mail box for 3 months.  However we don't want to keep an E3 or E1 license attached to the account.   I have a retention policy in place for the users mail boxes to delete after 3 months, but can't figure if I still need to have it licensed.  I have read that the easiest way is to just make the mail box a "Shared Mailbox" then remove the license to start the timer on the retention policy.  Any other ideas or is it possible to add the retention policy to a mail box and then remove the license and have the mail box delete after 90 days.

[#2 · Accepted solution]

Shared mailboxes still require a proper license to be assigned for retention processing, refer to https://docs.microsoft.com/en-us/office365/servicedescriptions/microsoft-365-service-descriptions/mi...
I'd recommend using Inactive mailboxes instead, as they allow you to free up the license: https://docs.microsoft.com/en-us/microsoft-365/compliance/create-and-manage-inactive-mailboxes?view=...