Special K is RU.
All the official hex releases are upgrades to beat the latest ECMs not the latest monthly update codes. There were two Kev 1.65's the fake was 1.64 with monthly codes added, the real Mr Sport 1.65 release was a C1 30 command tweak - check the readme's out.
Same goes for Keylog - there was a fake 6.2f and so no official 6.2f release was made.
Current hexes that can be AU enabled are Keylog 6.2h and Threat 4.03. You must use non-public MK/PPUA codes to activate them and so you need access to a valid subscription OSC to extract them from. Any public MK/PPUA codes released with an AU hex will be zapped by ITV.
A hex will last as long as it doesn't receive an unknown ECM. You can still use old hexes - they work but get hit more often. So the newer the hex, the more ECMs it can handle, the less frequently it will fail - but it will fail sooner or later.