Bukkit

• Carpet movement doesn't trigger physics. This means (for example) that if you place sand on the carpet, it won't fall when you move away.
• The carpet can now pass through fluids, so you can use it for underwater cruising or as a boat.
• A new permissions node for /mcs. Everyone has it by default. That means /mcs is reinstated. It may be removed again, however, since its reinstatement is a result of two different people working on the plugin without knowing what the other is doing.
• You now can't use /ml or /mcs if you don't have permission for /mc.
• The /ml command now takes an optional argument (ring, centre, center, both) to specify what type of light you want.
• Suffocating people with /ml carpets should be harder than it used to be. Unfortunately, it's still possible.
• Improved the piston protection to prevent pistons from stealing material from a carpet. Now works both on push and on pull.
• You can change carpet materials in-game, and each player can have their own choice of materials. To do this, use /mc or /ml followed by the material name (eg GLASS, JACK_O_LANTERN).
• You don't take fall damage while on a carpet.
• Carpets are saved through server shutdown, so you no longer need to worry about where you are when you log off.

When taking a carpet near cacti, you may see a flicker of glass adjacent to the cactus; this is the result of a failed attempt to fake glass beside cactus, since cacti popping off is not an aspect of physics (unfortunately).