We are pleased to announce the release of iDefrag 5.1.7. Changes in this version:
Fixed a problem with code signing on one of our KEXTs (this was caused by an update to Xcode that tried to take over management of code signatures, but which unfortunately doesn’t appear to work properly for us). This will cure problems some users are seeing on macOS Sierra (really, this time). Our apologies to those affected.
Note that there is still a distinct possibility that your machine will take a long time to shut down on the restart/shutdown immediately subsequent to installation of version 5.1.7. This is a problem with Sierra itself and has been reported to Apple. You can read more here.