Buildcraft

4.2.1

• Fix: Gold and Void Item Pipes work properly again. (SandGrainOne)

4.2.0

• New: Added Emzuli Pipe, a Gate controlled Extraction Pipe. (SandGrainOne/CovertJaguar)
  
• Change: Fillers no longer have a "crafting" grid, and can be controlled via Gates. (CovertJaguar)
  
• Change: Oil Springs produce 4x as much Oil as before. (CovertJaguar)
  
• Change: Pumps can be disabled by applying a Redstone signal. (CovertJaguar)
  
• Change: Allow draining of Fuel from Combustion Engines. (CovertJaguar)
  
• Change: Renamed Lapis Pipe to Lazuli Pipe. (CovertJaguar)
  
• Fix: Register all remaining Items properly with FML so that they will survive a 1.6->1.7 world upgrade. (CovertJaguar)
  
• Fix: Players can now see pipes placed by other players. (CovertJaguar)
  
• Fix: Block Harvesting now calls the appropriate new Forge Events. (DemoXin)
  
• Fix: Fixed Oil and Fuel Fluid localizations. (CovertJaguar)
  
• Fix: Diazuli Pipe should now better handle overflow situations similar to how the Diamond Pipe works. (CovertJaguar)
  
• API: Added API package and dependency information for new FML features. Should reduce API conflicts going forward. (cpw)
  
• API: Rewrote Filler Pattern API. (CovertJaguar)
  
• API: Added a new function to the Assembly Table recipe API that supports the Ore Dictionary. (taelnia/CovertJaguar)
  
• API: Moved ILaserTarget to the API so that addons can now create blocks that accept power from Lasers. (CovertJaguar)
  

Caveats

Requires Forge for MC 1.6.4 (9.11.1.953)

You must install this version first if you plan to upgrade your world to MC 1.7 eventually.