I went to join my world and it asked me to choose between two versions to sync, I chose the most recent one. Once I chose it though it didn't load all the way through, it basically synced half my world. I went and looked around the world and there were items floating where I had built my recent stuff. I had 100 some MB saved and it gave me 55 MB once I synced it. I'm not sure what happened or if it can be brought back to where I left off.