eli5: When an app updates, how are people on the old version still able to use it?

Question

I know this isnt the case 100% of the time but could someone pls explain. sorry im dumb and bad at tech

In: 0

Answer 1

It depends on the update, but in general good programmers/architects ensure backwards compatibility. Particular if you’re creating apps used by millions that won’t be updating at the same time etc.

There are updates/changes that absolutely will NOT work backwards – they’re rare and “we” try to design code to avoid them. But in some cases, we decide that “doing this in a completely different way is so much better than the trouble of ensuring everyone must update”. In most cases you design things to work with multiple versions.