The Asterisk.org development team has released Asterisk version 1.4.21.1.

This release includes a critical bug fix for 1.4.21.  All users that experienced lockups when upgrading to 1.4.21 should have their issues resolved with this update.

Asterisk 1.4.21.1 is available for download from the downloads site:
 * http://downloads.digium.com/pub/telephony/asterisk

Thank you for your continued support of Asterisk!