- Add IPAddr#prefix
- Add IPAddr#loopback?
- Add IPAddr#private? [Feature #11666]
- Add IPAddr#link_local? [Feature #10912]
- Reject invalid address mask [Bug #13399]
- Warn that IPAddr#ipv4_compat and #ipv4_compat? are deprecated [#Bug 13769]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60270 b2dd03c8-39d4-4d8f-98ff-823fe69b080e