Put following condition of frame of UICollectionView
.
if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7.0)
collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(x, 20, width, height)];
else
collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(x, 0, width, height)];
For deeply understand refer following question/answer;
iOS 7 status bar overlapping UI
iOS 7 - Status bar overlaps the view
Status bar and navigation bar issue in IOS7
Storyboard-set iOS 7 Status Bar not shown in right style
Storyboard app run on iOS 7 OK but Navbar shift view on iOS 6.1