No update for iphone 4

My app wont let me log in anymore because of the new update but when I go to the app page, there isnt an open to update. It just says "open" like its already up to date. This can only mean that my phone and iOS version are not compatible with the update so it wont even show an option to update.

LadySaigo about American Savings Bank Hawaii, v2.0.5002