Document introduction of the ActionController::UnknownFormat exception
Document extraction of actionpack-xml_parser
Improve docs for UpgradeSignatureToEncryptionCookieStore
Document the switch from memcache-client to dalli
Document rails-observers extraction
Document caveat from 5b3bb61 which fixed handling SCRIPT_NAME from within mounted engine
Document sass-rails asset_url deprecation
Document removal of assets:precompile:primary
Document change in routes using match
Document ActiveRecord::Fixtures becoming ActiveRecord::FixtureSet
Document the deprecation of ActionView::RecordIdentifier
Document common deprecations
Document that scopes require a callable object
Document introduction of ActionDispatch::ParamsParser::ParseError
Merge pull request #9495 from trevorturk/upgrade-guide

Add some more documentation to the upgrade guide