We are currently looking at upgrading from 12.4 to 12.5.1. We are running Exchange 2016 with outlook 2016.
Does anyone know if you need to upgrade the outlook addin for users during this upgrade?
you can update the add-in as well but there is no need to. An EV 12.4 add-in can still be used with a 12.5 server.
EV 12.5.2 should be somewhere around the corner just in case you'd like to use the latest release.
The Enterprise Vault Outlook Add-in is backward compatible up to one major version. So if you're users are having the Outlook Add-in EV 12.4, it will work with the EV Server running v12.5.1. The users should not be facing any issues. You can slowly upgrade the Outlook Add-ins over a period of time (a few weeks; depending on the size of the Organization).