Minecraft wiki entry for Discovery_Update, associated text: 1.1.1 and 1.1.2 were released to fix various bugs.
1.1.3 added fossils, as well as various blocks to the Nether.
1.1.4 and 1.1.5 added various skin packs to the Marketplace. 1.1.5 also saw the Marketplace extracted to its own library, so that updates to the Marketplace would no longer require version upgrades.
1.1.7 was released exclusively on iOS to add support for Internet Protocol version 6.