On July 5, 2023, ns-3.39 was published. This page lists some issues that have been fixed in the mainline since that time. The maintainers may make an update to this release to cover some or all of these issues.
Python bindings do not work for ARM-based Macs
Importing cppyy currently does not work for Apple silicon (Macs with the M1 or M2 CPU), as discussed in this issue. There is no current workaround, as this appears to be an upstream issue.
Use of scratch directory for programs using openflow and other modules with external dependencies
Programs in the scratch directory that rely on special module enabled definitions (e.g. openflow, click, BRITE, MPI) may not have those compilation definitions enabled, and users may be better off creating such examples in the module example directory instead. This limitation is fixed in ns-3.40 release, and is available in this patch.