As predicted last time, the new TechTool updates are out. However, the MicroMat web page notes that the TechTool Pro 1.0.6 Updater "is not fully 8.1/HFS compatible. Version 1.0.7 will be and should be released in a few weeks."
Tom Johnson discovered that TechTool 1.1.6 saves the PRAM data in a different way than 1.1.5. If you use TechTool 1.1.6 to restore your PRAM using a 1.1.5 PRAM Save file, you will likely get a system freeze.
Too early to tell if this is a general problem, but...Dick Platt found that TechTool Pro 1.0.6 reported read and write errors on his just-formatted hard drive (which was running just fine). TechTool Pro 1.0.5 said the disk was OK.