Sorry but upgrading from what?
Either way - you would be better off not getting this particular model.
There are going to be new models but due to the global silicon crisis - it’s a slow process at the moment.
If you currently own a LEM T (DM100) you would be better off waiting - in my opinion.
The S999 APPLLP is not supported by almost everyone - including us.
Adding custom faces is also unsupported on these as far as I know.