For 2.1 compatibility, in addition to updating info.json, the following change to mech-armor-animations.lua worked for me:
Change the "if animation.armors and flib_table.find(animation.armors, "power-armor-mk2") then" to check for mk3,
change the index = flib_table.find(animation.armors, "power-armor-mk3") to search for kr-power-armor-mk3,
and then instead of flib_table.remove, use table.remove.
Same for mk4.
