This was news to me so I thought I’d share:

Everyone, there will be MQTT name changes in the next release of the software. There is nothing to worry about, your names are safe. However the change caused addons like Z2M (and other MQTT integrations) to update their discovery information. As it stands, Z2M will not be able to release a version with this fix until September 2023. During that time a warning will be in your logs indicating that there is an issue. You can safely ignore this warning. As of this writing, there may also be an accompanied repair. You can also safely ignore this repair.

Once Z2M updates, the warnings will go away.

Again, during this whole transition period, your names and the default device names should not change. Please keep us informed if they do change.