Update says App not compatible – CPK Rewards Review

I've been using the CPK app for longer than I can remember, and on this iPhone5 (no s). Sept 2017: Update says "requires 10.3.3, but can download latest compatible app" Stupid app developers, this is 10.3.3 - on an iPhone 5. (Your wonderful new app is not compatible with "old" iPhone5 even if running your minimum OS version.) January 2017: Today the update said "Update is not compatible with your phone"
Review by koltovli on CPK Rewards.