The latest version of Minecraft has landed in version 1.5.3, mostly looking to fix a few crashes as well as one or two issues with the Xbox One version of the game – additionally it does (the post) make a reference to some users losing inventories and character progress and some tips on getting this restored.
Missing Inventories after Updating to 1.5.0:
Some players may have lost their item inventories and character progress after updating to 1.5.0. To recover inventory from a player that was lost, you will need to:
Have had a Microsoft account or Nintendo account tied to that player when you last saw the player with its previous inventory. Without this, your data cannot be recovered
Do not uninstall/reinstall the game on the machine you last saw your old inventory on – this will destroy the cached data needed to recover your lost inventory. Merely updating the game should be fine
Log in to the same server, which has been upgraded to 1.5.3, from the same machine you last saw your old player/inventory on
Be in an area which allows for chests to safely spawn. If you aren’t, the game should inform you, and try again the next time you log in
Without the Microsoft account or Nintendo account and the same device with the original data, the data cannot be recovered.
Xbox One worlds that were not appearing after updating to 1.5 will once again appear on the Worlds screen (MCPE-35364)
Fixed several crashes that occurred during gameplay
Fixed a crash that could occur for the host when another player leaves the game
Fixed a crash that could occur when joining a world that was converted from Xbox One Edition
Fixed a crash that occurred when placing renamed items in an Anvil’s output slot
Fixed an exploit that allowed custom skins with custom and invisible geometry, causing unfair advantages in multiplayer sessions