Bukkit

(ok, deep breath...)
5.0.51:
+Fixed +1 block placement issue on the East and South of regions
-Removed 8 block buffer zone around regions for dumping buckets that was causing problems when regions were close together. (yes, its finally fixed!)
+Added a listener to prevent water/lava from flowing into protected regions from outside them (as a replacement for the 8 block buffer)
+Added per-world EnderDragon Protection
+Added WorldEdit support (limited to region creation atm, enabled in generalsettings.config)
+Fixed file not found stacktrace spam in the console that occurs after renaming a region
+Added getRegion(location) to API and GRM
+Added getRegions(location) to API and GRM
+Changed expandmax from static 256 to World.GetMaxHeight
+Added dispenser locking
+Added isforsale check to the buy command
+Added Restrictions.config for custom restrictions
+Changed RestrictionParameters to use restrictions.config
+Changed GRM.doesExist to doesRegionExist for clarity
+Tied ownership to creation limit, players are now restricted in how many regions they can own based on how many they can create
+Added size checks to region modification to prevent players from expanding a region beyond their restriction limit
+Added gamemode switching regions
+Added piston listeners to prevent pistons from interacting with protected regions from the outside
+Added listener to prevent enderman pickup/place in protected region or globally +Added a command to enable/disable said enderman protection
-Removed "Price :" from for-sale signs to allow more room for the price
+Added commands to set region gamemode and enable/disable it
+Added command to list regions owned by player
+Third major code clean-up (consolidated code using new methods, removed unnecessary code, duplicate methods)
+Added new permission nodes to PermChecks
+Updated help text
+Changed restriction parameters to use worldmaxheight if restriction height is greater than worldmaxheight
+Re-added canBuild alias for canBypassProtection in Region class
+Added Group changing commands (and everything that goes with it) +Fixed Permissions modification (still a coding nightmare though :| )

Check the wiki for new commands and permissions

The new water/lava listener reportedly may cause performance issues on servers with a large number of players. I was never able to recreate any performance issues in testing (that wouldn't have occurred anyway) so I'm releasing it as is. If you have performance issues after updating/installing Regios, please report it.