Please click the following link to download ns-3.30.1, released September 18, 2019. ns-3.30.1 updates the original ns-3.30 release from August 2019:

For users of ns-3.29 release, two patches are available to update code to ns-3.30.1. A source code patch to update ns-3.29 release to ns-3.30 release is available here. Following that patch, a source code patch to update ns-3.30 release to ns-3.30.1 release is available 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.

The sha1sum of the ns-3.30.1 release file is 7a94f4d17b6d21d10d80693df59437eff918462b.