How long do most apps normally support a previous version of iOS for?

[max2]

6 months, 1 year, more ?

 

[C DM]

6 months, 1 year, more ?

Don't think there's a particular number as it can differ from app to app and from iOS version to iOS version even. Some update relatively quickly, others not so lock; some support a few versions back, others maybe only one or even just the latest at times.