local-store.hh line 16
/* Nix store and database schema version. Version 1 (or 0) was Nix <=
0.7. Version 2 was Nix 0.8 and 0.8. Version 3 is Nix 0.10 and
up. */
^^^-- should be 0.9 I think
There is much to learn reading this code ;)
Marc