Today we released a QFE for .NET Micro Framework version 4.2. This is both an SDK and Porting Kit release and can be found at http://netmf.codeplex.com/releases/view/82448. The changeset for this release is at http://netmf.codeplex.com/SourceControl/changeset/changes/17284.
The only SDK change is for the PWM Type in the Microsoft.SPOT.Hardware.PWM.DLL assembly. The change to PWM is to allow the user to specify the scale that they are using which means that the new functionality supports a larger range and more precision in the wave forms. We changed the version of assembly Microsoft.SPOT.Hardware.PWM.DLL to 18.104.22.168. All other assemblies are unchanged and their version number is still 22.214.171.124.
PK level changes are documented on the download page. Noticeable changes are the signature for the PWM_ApplyConfiguration function to match the PWM enhancements at the SDK level, a FAT File System corruption fix, and some fixes to the lwIP drivers. We also made a performance improvement to the lwIP stack for closing TCP/IP connections and improved GC reliability in high memory pressure situations.
Since there is hardware available that has early versions of 4.2 firmware on them (although I think that they are all beta firmware), we will continue to have the original 4.2 release available.