The versioning nomenclature seems somewhat chaotic... here it says 10.5 and their current version is 10.10 and on the linked page they refer to 10.1 and also talk about 10.50.
I guess that 10.10 == 10.1 and 10.5 == 10.50 but it is a bit confusing...
Oh, and the download crashes with SIGBUS on my MacPro running 10.6 :(