squashfs-tools-3.3 has been in the tree for almost 6 months now and there are no open bugs. Note that genpatches has been carrying the same version of the squashfs kernel patch since 2.6.24. There have been improvements in the capabilities of the filesystem itself in 3.3. Therefore, it is possible that using the latest tools would produce filesystems that are incompatible with 2.6.23 kernels because genpatches contains the 3.2 patch for that series. However, I am not sure that this is a serious impediment as 2.6.23 is verging on obsolescence in terms of maintenance. One option would be to add some ewarn info pointing out this potential pitfall. Another would be to stabilise squashfs-tools-3.2_p2 instead, until 2.6.23 disappears (an option that I personally would not favour as I think that it is sane that the userland tools should match the patch in the current stable kernel).
I actually did this a couple days ago though I hadn't seen the bug. I marked it stable on every arch with a stable 2.6.24 kernel. I did mark 3.2_p2 stable for 2.6.23, though. Thanks for pointing that out.
