I have to update an app build with Xcode 5 for iOS 7.
Unfortunately, there's not enough time and money to migrate it to iOS 8 by now.
Will Apple reject the app, when i'm trying to publish it to the AppStore?
Thank you!
In answer to your question, we submitted an application update built with xCode 5 recently, and it went through just fine.
Apple have previously sent an announcement to developers giving advance notice of any change in the minimum required xCode version.
On 13th Jan 2014, they announced that apps had to be built with xCode 5 and iOS 7 ready as of 1st Feb 2014. We can assume that they will follow a similar schedule for iOS 8 - if they actually fix all the bugs in it...