Minecraft – Outdated Servers Unable to Access World

This means that the server you are attempting play on a world/server is using an outdated version of the game, therefore not allow you to play. Say, you have Minecraft Pocket Edition 0.9.0, and you attempted to connect to a server/world using 0.8.0, you'd get that error message.

Ensure "local server multiplayer" is enabled in options.

Ensure none of the devices is using a VPN.

Ensure ALL of the devices have the latest version of Minecraft PE. If that's not so, there's no way it's going to work.

To update an app on iOS:

1. Open App Store app from home screen.
2. Browse into updates tab.
3. Scroll down to find Minecraft PE.
4. Press the "UPDATE" button next to the game.
5. If needed insert Apple ID password.
6. Wait for update to finish.

Repeat this for all iPads.

Ensure all the iPads have A DIFFERENT MINECRAFT NAME!

You can change the name in Options menu, from "Steve" to something else.

If it still doesn't work, this might be a issue with Unique Device Identifier of Minecraft. Reset it by uninstalling and reinstalling Minecraft PE. This will unfortunately remove the worlds.