We have actually be using an internal navigation framework that is unfortunately quite tightly coupled to our app. It's been working very week for us which is why we decided to make an open source "clone" of it. Our original intention was to migrate our internal navigation library over to the open source clone we made. However, with the realities of life, we haven't had the time to actually do that yet which is why we haven't been maintaining it.

Like Leland said above, we're still working hard and making exciting progress on React Native but we continue to invest in native platforms as well and product teams make a case by case decision on which one to use.

Hope that clarifies things a bit :)