Running Linux MInt.  No problems with my previous Minecraft Launcher (the most recent 2.1.12xxx).  I uninstalled/reinstalled to upgrade to 2.1.13086 and now MineCraft shows no saved worlds.  When I look at my ~/.minecraft/saves folder all my worlds seem to be there.

I tried creating a new world.  That worked, but Minecraft still only shows the one new world.  When I go back to ~/.minecraft, all my old saves are there but not the new one.

It seems like Minecraft is looking elsewhere for my saved worlds but I  see no documentation on that change, and no forum advice about it possibly being in a different location.

UPDATE: when I use the settings to point to the old ~/.minecraft folder, Minecraft now shows no worlds saved, new or old.