Mike, when I installed the http://n0nb.users.sourceforge.net/dll64/libhamlib-4.dll as a replacement for the version in my WSJT-X v2.5.3 directory \WSJT\WSJTX\bin as you gave instruction to do, I receive a failure on the hamlib when trying to connect to my remoted IC-7300 that is connected over Win4IcomSuite server and client programs. The remote program uses com0com program to send the C-IV data to the remote site, and in com0com I have setup com ports 40 and 41 for that purpose. It does work correctly with the new version replacement on my local IC-7610 radio. It also works correctly on the libhamlib-4.ddl that installs normally with WSJT-X v2.5.3. I guess I am saying the version that was corrected now breaks the connection over my remoted IC-7300 radio.

By the way, I was testing the new version you put up on sourceforge because I was having erratic operation of the VFO A and B not setting to the correct frequency at times was I was making contacts. I had been using the Split setting in WSJT-X radio panel.

I am using Windows 10, 64-bit, and WSJT-X v2.5.3 addressing the updated hamlib-4ddl in this message stream.