Well, there actually was a fairly good reason for delaying announcement of 3.1.9-3.1.11, because I think 3.1.12 is a bit more stable than those releases.
The most important change, introduced in 3.1.9 and refined in 3.1.10-3.1.12, is that the PCMCIA drivers now try to use PCI interrupts for CardBus devices. ISA interrupts are still used for 16-bit cards. This matches the interrupt scheme used by Windows, and this is the only scheme supported by some newer CardBus bridges. There still seem to be a few quirks to work out, but this feature now seems functional on the vast majority of platforms.
Starting in 3.1.9, there are a few more wireless drivers in the base PCMCIA distribution. Most of these were also updated in 3.1.12.
Among the more important bug fixes, the new drivers should fix problems with 3Com CardBus cards not waking up after a suspend. Also, there is a workaround for a problem with modem cards not working if configured for unusual IO port addresses (i.e., not one of the standard IBM PC port addresses): this is actually a kernel bug, but I could avoid it with a change to /etc/pcmcia/serial.
There have also been a number of changes to accommodate 2.3.* kernels. The PCMCIA support in the 2.3.* kernel tree is still experimental and has some serious unresolved issues. I hope to get to the point where it is possible to also build all the standalone PCMCIA modules against the latest kernel, but I'm not quite there yet; the modules work now, but the configuration process needs to be cleaned up.