Issue with my friend joining my world

I went onto the beta version of Minecraft, then I deleted it because my friend couldnt join my world, so I returned to normal minecraft.  I dont have the nether update (what is normal for my xbox) and neither does my friend (we're on the same version) However, he can't join my game and I can't join his.  I also don't have access to one of my worlds because it was saved on an updated server.  Please can you help

Kind regards

Charlie