If you are looking to play Wii U titles on your mobile device, several alternatives currently provide more stability than experimental Decaf builds:
The main Decaf GitHub repository only provides releases for desktop operating systems. While the emulator's open-source nature means someone could theoretically port it to Android in the future, Decaf's current development focus remains on desktop performance and core research. The Better Bet: Cemu for Android decaf emulator android
If you are a developer starting this project: If you are looking to play Wii U