It seems to be a reasonably open secret (by which I mean SOTM bar chat ;) ) that Mapbox is currently putting most of its development efforts behind Valhalla; and that many of the developers formerly working on OSRM are no longer involved with it.

From a distance it looks like OSRM is in "maintenance mode", which is obviously much better than being abandoned, and it's good to see PRs like #5197 moving the project on. Nonetheless the fast pace of development since 2013 has evidently abated for now.

OSM data does (slowly) evolve and if OSRM is to continue to be useful then it'll need to keep up with this. Much of this can be achieved via profiles, and keeping these up-to-date is fairly trivial, but there are some more significant data issues which will require real engineering commitment (I'm thinking in particular of #4439 to address the increasing number of multiple-via-way restrictions, but there will be others).

So it would be good to have a steer as to the future direction of the project. Does Mapbox intend to continue maintaining OSRM in perpetuity, or only until Valhalla reaches feature/performance parity, or...? Is there any interest in moving it to the community (a la CartoCSS)?

(FWIW I'm not concerned for cycle.travel, which uses an extensive fork of 4.9 and which is very unlikely to return to trunk, but I do use current versions of OSRM for some contract work. Looking at the issue tracker here, there is still a lot of interest in OSRM and people are building solutions on top of it.)

In any case, thanks for supporting so many great improvements over the last five years and being good stewards of the project!