I have just loaded iOS 7 and my calendar app does not now accept events !! It has also wiped all events already stored.

I have exactly the same problem though it happened all of the sudden. I had been using ios 7 for a while now and even after the update of it everything worked fine.. untill just couple of days ago. Siri is acting up. just cant do anthing I ask her most of the time. my favorite contacts just got errased completely. somehow I managed to get them back with some help from the forum. and now this! all events are erased and I cant add new ones! very frustrating!!! someone please help!!!!!

I also have iPhone 4

ajisrel11 and chelsy.pl;

Did you ever receive a solution to your issues with the calendar and not allowing you to add new events to the calendar on an iPhone4? If so, could you share them as I am having the same issue now and cannot find any help for it.

Thanks.

Tom

Go to settings - icloud- turn calendars to ON and it should be fixed. If it is On turn it Off first.

Yeah just like fromsouth said... That should fix it. What also worked for me is I hooked it up to my laptop and retrieved my phone's backup form iCloud. That also fixed it.

Unfortunately this happened to me a few times now and I don't know why it happens in the first place! Would be nice to know....