auto update has turn the app to demo version v0.99A automatically. So, better turn off mobile data or just block the app from using internet.
Cheats is easy tho. For you who dont know follow this step
1. Turn xxx.apk to xxx.zip
2. Open it with ZArchiever (rec) Find "items.json" and "system.json" and extract (i recommend you extract it to save folder)
3. Open web saveeditonline(dot)com (this one is easy and simple so i recommend it)
4. Upload the items.json and system.json and last upload your save file. Fyi file1.rpgsave is (autosave) and file2.rpgsave is (save slot1) so on
5. Enjoy edit your stat and add item by simply change (0) to (99) or whatever. but pay attention to "edit prohibited" or "dont edit" since it may cause the game crash
6. After finish editing, click download file. Copy or cut and paste it to the save folder. Feel free to overwrite existing file or just change it to another save file (ex: file3 or 4,5,6.rpgsave, it will create new save file in game)
OR if you understand how .json file mechanic works, feel free to edit items, weapon and armor value to your desires like (dmg+999 or add stat, etc) by upload weapon/armor/items.json to the web and paste change the existing file. Just back up files before editing just in case the game crash.
Enjoy
The game is boring to soon when you "overcheat" so, do it in moderation