App Force closes during reservation change

Heavy heavy Zipcar user. Everything was fine when I was on the old app for my 5s. Get a 6s, update to new app, and now if force closes EVERY TIME I try to "change reservation". Which is a HUGE part of using the app. Can we please fix this bug? Ive deleted and reinstalled, same result.

Jaws Guy about Zipcar: cars on-demand, v4.0.11