Custom Skins Not Working On Some Devices

My friend is playing minecraft pocket edition 0.11.1 (the latest official release he can download from the appstore at this point in time) on his iPod Touch 4, running iOS 6.1.6. He has encountered a bug where custom skins do not work, it always says "that's not a skin, silly" even though the exact same skin works on my iphone 5 running ios 8.3, on minecraft pocket edition 0.11.1. I really think this is happening to every device running ios 6.1.6, as my other friend is expierencing the exact same problem. Please Fix! Thanks for reading,
Jake M
P.S i have attatched images of error.