In America I wanted to use an old moto g5, since it had 4g LTE and was all I needed. Every version of android between 7-14 is available for it through custom ROMs, and some people are still releasing security updates. But it turned out ATT and others “Whitelisted” it from their networks for being too old. Apparently when the switchover happened ATT sent everyone with a whitelisted phone a cheapo garbage phone as consolation, and nudged them to buy a new phone. Super scummy behavior.