Change-Id: I274a7429130db05c2dc8bba9bd32d28b933747d3
by adding a new configuration variable $wgApplyIpBlocksToXff (disabled by default).
=== Bug fixes in 1.21 ===
+* (bug 40617) Installer can now customize the logo in LocalSettings.php
* (bug 40353) SpecialDoubleRedirect should support interwiki redirects.
* (bug 40352) fixDoubleRedirects.php should support interwiki redirects.
* (bug 9237) SpecialBrokenRedirect should not list interwiki redirects.