Hi, I've noticed that there were some attempts to re-use the older 10.5.6 AppleUSBMultitouch.kext with the 10.5.7 updated installs. Though it works, I'm not sure if there are side effects to doing that, though it has been reported to work. I have come up with easier way of updating the 10.5.7 AppleUSBMultitouch.kext to support 4 finger gestures without having to use the older kext or perform any kext replacement. Here is how: WARNING: This mod is only applicable to the 2008 Penryn MBPs that were released just prior to the unibody models. Please make sure to follow these steps exactly! Read all the steps before performing any of them! Download the attached Info.plist.txt file into your home folder. Open Terminal and cd into your home folder. Like this: Code: cd ~/ Check to see if you have the Info.plist.txt in your home folder. Like this: Code: ls -l Info.plist.txt Please repeat all the above steps again, if you see the this: Code: ls: Info.plist.txt: No such file or directory In the subsequent step you will be requested to enter your password to complete some of the commands. Please keep your password ready and enter it when requested! Execute the following commands one line at a time in Terminal: Code: mv Info.plist.txt Info.plist sudo cp Info.plist /System/Library/Extensions/AppleUSBMultitouch.kext/Contents sudo rm /System/Library/Extensions.mkext Reboot your MBP. After rebooting your MBP, the multi-touch gestures should work. If it doesn't work please post your problem in this thread. If you were to do a diff between the Info.plist attached here against the one in your MBP (before you replace it ofcourse), you'll be able to see what the changes are to enable 4 finger gestures support. These changes could also be applied to future 10.5.x updates to enable 4 finger gesture support.