disappearance

After installing the new version, I went to minecraft as usual, to my old world. Then he saw that I was missing: "Copper (all copper, from ore, ingots, blocks in a chest, to a lightning rod). Iron golems, residents (ALL), cats, dogs, even my horse skeleton (. Lost path. Mine a small building made of blocks of copper also disappeared, leaving the vines hanging in the air, but what scares me the most seems to be that all the copper ore from the world I loaded has disappeared.