I've got a Galaxy S4 from Verizon. I used it on a T-Mobile account that I got for foreign travel and it works fine.
Now suppose I switch to T-Mobile permanently, and a new Android version comes out.
Can I put the Verizon SIM card back in and get updated, even if there's no Verizon account for the phone?
Or is there another way to get updated?
Or am I stuck with the current version unless I go back to Verizon?