Comment by d3Xt3r

SailfishOS is another popular mobile Linux distro you should be aware of - it's been around for a long, long time - in fact its heritage can be traced all the way back to Nokia's Maemo OS (circa 2005), which became famous in the community with the Nokia 900.

And then in 2010, Maemo merged with Intel's Moblin to become MeeGo (featured on the Nokia N9). The MeegGo engineers who were let go (due to Nokia x Microsoft) then created Mer, and eventually started a new company called Jolla, who created SailfishOS based on Mer.

It's been 13 years already since SailfishOS was out, and if you include the Maemo heritage, it makes it the oldest surviving mobile Linux distribution.