Minecraft update

My minecraft won't update to the newer version. Normally a would go into Minecraft and a page would show up and I would be able to press a button that started a update. But not now. 
The reason I found rhe issue was that my sister got the page, but not me. And then we tried playing together but it didn't work because I had a "out of date version". 
I've tried going into AppStore and then into Minecraft to update, but it said that there isn't any updates available..? 
I've tried turning the iPad off & on, but it didn't work.

So my question is, how do I update Minecraft?