Mobile line call verification rollout-Stir/Shaken

I know that caller verification is rolling out using Stir/Shaken across landlines and mobile systems.  I read an article from Xfinity that says only "certain" Xfinity mobile phones have or support this caller verification feature as of now.  Is there any additional information that goes into more detail on whether some phones will end up never getting this feature or it is just a rollout timeline process where all Xfinity mobile phones will eventually get it?