It looks like there's been an issue with the Calendar in the new iOS 7.1.1 update. Unfortunately, we are not able to fix this bug if this is affecting your EasilyDo Calendar, however we can provide you with some links that will help you get your iPhone Calendar running. We did some research and found other iPhone users having the same issue, we'll include these links below:
We hope this helps and we're sorry for any inconvenience this has caused our users. If you have any other questions, you can still email our Support and we'll get back to you as soon as we can.