Failed to convert 256x256 type world in infinite world.
Need some help with this. You'll need an account on bugs.mojang.com. If you do have an account, please vote it since I have shown the proof. It's a blue color button a little below on the left.
Could you share the bug details here? Maybe we can help too.
I have an old types world in Minecraft. I try opening it in the new version of Minecraft but the game crashes. There's an open to convert the old type world (256x256x128) into new type world (infinite). But if it click the option the game still crashes. This is the video link. Tell me if you need more. [0:26] in the video is my home screen, you may ignore.
Ok. My suggestion is to find an older version of Minecraft and install it, then try to convert it, then if it works update back to latest. It looks like you are on Android so you can install old apps via APK files.