Update Failed on Android TV

Hello,

i currently have this nightly version installed on my Nvidia Shield Android TV:

kodi-20160918-cc9c142-master-armeabi-v7a.apk

Now i want to update to:

kodi-17.0-Krypton_beta2-armeabi-v7a.apk

After installation it tells me “failed”…. I wonder why?