This is awesome App Icon Template for iOS 5,6, 7 and 8, which was created by appicontemplate
Format: PSD & Actions;
Size: 22.1 MB;
License info: completely royalty free. You can know more license info details on the author’s blog
It seems that the author will keep updating this freebie
You can download this free iOS 8 App Icon Template PSD file from author’s blog, click here