When I did it for the other network, I did it in 3 pieces to go from old protocol to current.

The first network upgrade was just another 0.8 branch release which fixed the difficulty adjustment algorithm.
Afterwards, a 0.13.0 release occurred to usher in BIP66/BIP65 by consensus.
Lastly, a 0.14.3 release was performed to complete the network upgrade.

Along the way, this included the support for BIP 32 as well as a SegWit.

I don't think we need to go the scenic route here but its certainly a possibility we can entertain as well.

Best Regards,
-Chicago