What has always been bugging me and every other MCPE player is that, The Nether Roof is off limits and you can't build on there.
Java players can build on there and just have a big advantage when it comes to travel. I believe that us MCPE players deserve to be able to build on the nether roof.
And yes building on the roof has been a bug for Java players, but a bug that hasn't been patched for a decade is a feature by then. So add building on the nether roof for MCPE!
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We're tracking this issue in MCPE-18263, so this ticket is being resolved and linked as a duplicate.
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