I was not hired to work on vB5.
I was hired to work on vB4, after the rest of the team (except Freddie) moved to vB5.
Freddie & I worked on vB4.1.5 initially, and then vB 4.1.7 to vB 4.1.12, & finally vB 4.2.0.
Neither of us worked on [or even saw] vB5 until the end of May (after we finished with vB 4.2.0).
Danco also joined the team on vB4 initially, and moved to vB5 after 4.1.12 was released.
Since then I have done bits of vB5 bug fixing, and some work on the hooks and extensions areas.
However, I spend a lot of my time working on [and managing] the VBC and VBG backend & sales systems.
Freddie also moved onto vB5 bug fixing, and is now heavily involved in investigating and fixing performance issues.