I've recently been making an adventure map & noticed the 1.7.6 was out, so I tried it & there was no changes, no iron trapdoors, etc (found my answer on here, it isn't a 1.8) so I switched back to 14w11b & now some of the items & quest books for my map are missing. Luckily, I made a backup yesterday.
MC-52649
1.7.6 makes changes to 14w11b saved map
Resolved
Duplicate
0
Dan Taylor
(Unassigned)
Unconfirmed
Minecraft 14w11b, Minecraft 1.7.6
Retrieved
You broke two good rules for avoiding corrupted inventories/worlds
1. Never downgrade.
2. Snapshots are not guaranteed to be stable.
You did follow the most important rule though 😃
Make backups!