Checking if unconfirmed_email has changed before to set update_needs_confirmation flash message.
Accept mail options in Devise::Mailer and deprecate headers_for
Added failing integration test for XHR invocation of SessionsController#destroy with `*/*' in the `Accept' header.
Fixed bug in SessionsController#destroy which caused all XHR requests, regardless of `Accept' header, to be treated as 'text/html'.
Merge pull request #2201 from al/bugfix-non_navigational_session_destroy

Fix bug with non-navigational requests being treated as navigational ones in XHR to SessionsController#destroy.
Update app/controllers/devise/sessions_controller.rb
Update copyright [ci skip]

Or as @rafaelfranca says: Happy New Year :fireworks:
Release v2.2.0
Update Gemfile.locks to latest patch releases of Rails and fix mocha to 0.10.0.t
Notify on campfire
Invalid YAML :bomb:
Install mongoid only on 1.9
Add failing tests for Issue #2204

For a point release upgrade, Devise should not throw an exception when trying
to downcase or strip globally configured keys. This would be a breaking
change in functionality and this test demonstrates the issue.
Call respond_to?(attr) before applying strip or downcase

This avoids calling strip and downcase on globally configured keys that may
not exist on all devise models. Fixes #2204, a regression introduced by
PR #2135. Also included a note about the intentional use of respond_to.
Merge pull request #2205 from latortuga/2204-regression-with-db-authenticatable

2204 regression with db authenticatable
Rename Devise::Mailer.translate() to something more inline with what it does.
Merge pull request #2206 from tigris/mailer_subject_rename

Rename Devise::Mailer.translate() to something more inline with what it does
Revert "update_with_password doesn't change encrypted password when it is invalid"

This reverts commit 10235f9d7204128e0daf17715b96e65df8e26e7d.
Release 2.2.1 with fixes for 2.2.0 regressions
Changed link_to to button_to for delete user

It is advisable to use link_to for mostly GET operations. Actions like DESTROY when presented as a link can cause severe vulnerabilities.
Hence using a button is advisable.