A major part of this in computing is security standards - old browsers and phones don't have encryption / controls that meet modern standards, plus manufacturer

A major part of this in computing is security standards - old browsers and phones don't have encryption / controls that meet modern standards, plus manufacturers stop supporting the OS or providing patches. The people operating mygovid & other identity apps would like the widest device support possible but to some extent their hands are tied by compliance requirements and what their security auditors tell them.