@scott

Another alternative if you just want internal communications is to set up a Nextcloud instance and use the Nextcloud Talk apps.

This is very slick and simple, but it only works within your instance, there is no way to communicate with other instances. This is good for situations where you want communications to stay in-house without sharing with outsiders.

Nextcloud is useful anyway for group collaborations etc, very nice and very easy, lots of add-ons.