When a building practice is too old and common to require its update to the current code and is still deemed safe enough. As long as the object/building that was allowed to forgo its updating is not actively changed/adjusted/worked on it is not required to be updated to the current code.
Due to historical connotations of this word, "legacied" has become a preferred term.
Due to historical connotations of this word, "legacied" has become a preferred term.