Drop support for upgrading from Nix <= 0.12
Drop support for upgrading from Nix <= 0.12

wmertens/nix,ysangkok/nix,dezgeg/nix,zimbatm/nix,rycee/nix,ehmry/nix,zimbatm/nix,dezgeg/nix,NixOS/nix,pikajude/nix,wmertens/nix,dtzWill/nix,ehmry/nix,layus/nix,rycee/nix,NixOS/nix,zimbatm/nix,bennofs/nix,layus/nix,peti/nix,layus/nix,ysangkok/nix,wmertens/nix,bennofs/nix,shlevy/nix,peti/nix,ysangkok/nix,shlevy/nix,layus/nix,bennofs/nix,peti/nix,rycee/nix,ehmry/nix,vcunat/nix,shlevy/nix,wmertens/nix,shlevy/nix,layus/nix,peti/nix,dtzWill/nix,rycee/nix,dtzWill/nix,NixOS/nix,zimbatm/nix,pikajude/nix,NixOS/nix,ehmry/nix,vcunat/nix,dezgeg/nix,NixOS/nix,dtzWill/nix,dezgeg/nix,shlevy/nix,peti/nix,rycee/nix,dezgeg/nix,ehmry/nix,pikajude/nix,dtzWill/nix,bennofs/nix,ehmry/nix,vcunat/nix,vcunat/nix