If you are looking for Myth III version 1.4 for OS X which is the last version of
Myth III to run on OS X (up to Mountain Lion, does not work on Mavericks)
You can download it by clicking here.

With regards to an update, I have been unable to find enough interested people needed
to continue to support Myth III. If this changes, updates are possible, but until then
I need to keep this on ice. If you are interested, email me at: mbagnall@gmail.com.