IMHO without the key to the repo you can't pull changes. Are you planning to fork it?
There will be no forking if everyone upgrades. And even if you do have a key to the repo - you still need everyone to upgrade - this is how crypto works.
Are you still working on this? I see a few offers to pitch in
No. It's DEAD.
1. The wallet that someone mentioned in this thread wasn't built from sources that are on Github. Wallet built from Github sources is incompatible with current blockchain.
2. I tried to contact Dev, he was online yesterday but didn't reply.
3. The network was supposed to generate blocks every 5 minutes (~288 blocks/day), but it currently does only 10-30 blocks/day, half of which usually are created during 1 minute.
Not sure why/who is pumping it, but I would suggest refraining from buying it.