Today we updated how our casters handle base station source information. Previously it used data from source form (description) and ignored the data that got with the base station connection request.
Now it use this request data by default, and only if 'Override source' is enabled, it will use data from form.
Screenshot 2022-12-11 at 7.17.37 PM.png
In this case, the format will be xCMR no matter what is in the RTK base connection request.
In your case, just keep 'Override source' disabled. And the format will be set automatically.