Need for on-prem Exchange Hub if you're an O365 EOL shop?

[Mughal1]

Hello,

I work for a company with a few thousand employees. We're an M365 shop but with an on-prem AD environment + hybrid Exchange environment.

We have an on-prem Exchange hub server that is being used for admin purposes, primarily for our end-user admin team for things like user mailbox / mail-enabled security group / DL admin. There are no on-prem mailboxes on this host.  Is it possible to retire this server and convert all the mail related admin functions that are typically performed on that Exchange hub server to using Powershell on our mail admin user machines with appropriate M365 admin access accounts/permissions?  If so, is there some other business/technical need/benefit for having on-prem Exchange if we're completely using EOL for all user mail services?

Thanks,

T.

[#2]

@Mughal1 If you are running in Hybrid mode then this may indicate that mail is flowing through your exchange server.  If however you have migrated to EOL, then the sole purpose of the exchange server is to give you access to the UI that can update Exchange Objects in AD which are then replicated to Exchange Online.

The guidance on removing the last exchange server changed recently and is published here Manage recipients in Exchange Server 2019 Hybrid environments | Microsoft Docs.  There is a list of pre-conditions that need to be followed.  

The key thing is to SHUT THE SERVER DOWN, but do not uninstall Exchange as this will remove the schema extensions that contain things like Email aliases.

Once this has been removed, you can still use the Exchange Management Tools which will give you the PowerShell capability to continue managing your recipients.

Alternatively, you could consider deploying a tool such as Atria which allows the user lifecycle to be managed through an easy to use portal.  You can find out more at https://www.getatria.com