When trying to install the game on android it asks if I want to 'update' even though I don't have it installed. When trying to update it then fails and gives the message 'App not installed as it conflicts with an existing package'
This is typically a conflict with another RPG Maker MV game installed on your phone, that was packaged using the same method I used.
Do you have any other game installed on your phone that runs on RPG Maker MV?
