First of all, bug 2059 has been squashed. This bug is an important one because it allowed the kernel to crash at any given moment, especially when there was a lot of input/output activity going on on the hard disk. The bug was fixed by Ingo Weinhold and Axel Dorfler.
A more important development is that Haiku now has build system support for mixing GCC2 with GCC4. Before these changes, you either built Haiku with GCC2 and have backwards compatibility with BeOS applications (but you used a very old GCC version), or you chose GCC4 which gave you an up-to-date compiler, but no backwards compatibility. The trick is that the runtime loader now supports checking for the proper version of the libraries needed; the runtime loader does this automatically on a system-wide level. As Stephen Assmus writes, "All this combined means Haiku can use GCC4 itself while maintaining our stated goal of binary compatibility to the large pool of GCC2 applications in an automated and transparent fashion."Currently in the works are a fully native port of Subversion, and Dorfler is working on fixing the device manager.