Compared to WriteLog Flex driver 12.26, this update only updates to the latest Microsoft and other third party libraries such that it provides installation compatibility with future versions of WriteLog. There is no new functionality, but, in the future, WriteLog installers will reject the older Flex driver installations and insist on this new one. WlFlexDriver1227B.exe The latest is now WlFlexDriver1227C.exe which installs exactly the same product as 1227B but fixes an installer issue that prevented installing on Win10 systems with certain policy settings.