It's active in that the mod works with no game breaking bugs, but I haven't seen any current comments from the mod author in a long time. Hopefully they're ok. I looked in every topic and the most current thing they've posted was in the comments back on january 6th.

We are rather enjoying this mod on my server, so I'd say its safe to use!

Yeah, I wanted to try my hand at modding, and i wanted to see how they got these amazing wyverns. I kinda know how to make full sized ones, but no clue on the saddles and the smaller ones. This mod is so epic tho.