Hypergryph issues codes from two channels and no others. A version broadcast and the announcement post that follows it carry the codes tied to that release, and several of those have expired with the version itself. Milestone and apology codes go out on the official social accounts. Maintenance compensation arrives as in-game mail rather than as a code at all.
A code circulating outside those two channels was not published by Hypergryph. Sites that generate codes, or that offer them in exchange for a login, are not distributing anything Hypergryph issued.