Today, I merged a large set of changes to the IAX2 channel driver in Asterisk into the 1.4 branch and trunk. These changes address both stability and performance issues. Normally, changes such as performance enhancements are not merged into the release branch. However, they just happened to be a side benefit of the work which resolved ways that the module could crash Asterisk.
We released Asterisk 1.4.11 today. It includes a fix for a security issue in the SIP channel driver. Check out the official posts on asterisk.org: