Upgrade issue?

Recently had a banking app stop working because it said that I needed to upgrade to at least OS 13. I thought it odd that while obviously not the newest phone my phone still works fone for what i need it for and i would have thought that for basic functions such as an everyday app a 4 year old phone is still a few years away from being obsolete for basic uses like that. So I checked by information to confirm I was on os12 and then to check for upgrades and it said that I was all up to date.

I'm not going to claim to be an amazingly tech savvy person but I feel like for the most part I know what I'm doing and my phone is just used for everyday personal use, nothing extreme but im aware that the phone supports OP 16. Is there some way to upgrade around the built in feature or did I accidently tuen somthing off that would block it from getting the latest OS?