The version number remains the same. If you look inside the update zip, you'll see that it actually contains a kernel, not a recovery. So don't worry about the TWRP version.OK, I decided to take the plunk and give the 2.6 kernel version a try, but seems like I did something wrong.
I'm starting from Quarx's 20130917 4.3 version, so I guessed I should upgrade TWRP as instructed in the first post. I downloaded update-recovery.zip, installed it and rebooted. However, TWRP's version stayed at 2.6.3.0. Since the updated version number isn't noted at the first post, I was wondering if anyone who had successfully installed 4.4 (and therefore upgraded TWRP as required) could pass me the right install instructions and the TWRP version I should end with.