Proprietary, with almost full sources to the standard library, however. There is indeed a bunch of half-assed stuff, but that's easy to ignore. In general, Delphi moves slowly and hardly ever breaks backward compatibility. Only the transition to Unicode in D2009—oddly not mentioned in the article, along with generics—was a little rough. Apart from that, decades old code keeps compiling/running without issue. It's mostly third party components needing updates sometimes, especially if they're shipped as compiled units or integrate with the IDE.
