R67, as in the version before R68. And yes, they are aware that it went end-of-support in 2014. Due to the switch from gated to routed, GAiA-based VSX wasn't feature-complete until R80.30, I think. R77.30 was the last management version which could manage R67, so they definitely can't do a single-step upgrade.
I don't think any features were lost from R76 to any subsequent version. Still, it's far easier to test vsx_util writing a version to the object than it is to test actually managing that version.