Please click the following link: ns-allinone-3.24.1.

A source code patch to update ns-3.23 release to ns-3.24 release is available here, and a patch to upgrade from ns-3.24 to the maintenance release ns-3.24.1 can be found here. Other patches to migrate older versions of ns-3 (back to ns-3.17) to the latest version can be found in the same directory; they must be applied sequentially to upgrade across multiple releases.