Official Release Considered a Snapshot

Put the summary of the bug you're having here

What I expected to happen was...:
I would see my(our) world in the world select screen normally

What actually happened was...:
The game told me I should beck up the world before loading in a snapshot

Steps to Reproduce:
1. Launch Minecraft
2. Go to world select
3. Hover over desired world

4. If the world is clicked on, you get the same type of message