Trapdoors: This update adds support for trapdoors as the top elevator block in both single block elevators and combination elevators. Trapdoors in elevators are non-directional meaning you can place them in any orientation and they will still work with trapdoors in other orientations. This has been done to avoid confusion as you can't really tell the difference from a trapdoor facing east from a trapdoor facing west (or any other direction) unless they are opened. Open trapdoors are not supported.
Internal changes: Some of the combination checking methods have been rewritten to support trapdoors as well as completely removing some methods as they were no longer necessary.