The TQSL application used by LoTW is free to download and use, and is available for Microsoft Windows and Apple OS X. If you are running anti-spyware or anti-malware applications such as Bit Defender, configure these applications to allow TQSL to run.
Note : TQSL can submit digitally signed QSOs and Callsign Certificate requests to LoTW via the internet. The firewall or another anti-malware application on your computer may by default prevent TQSL: from accessing the internet. Consult the documentation for the application you're using to learn how to declare TQSL as "safe" so it can access the internet.
The current version of TQSL is 2.3 . If you have an older version of TQSL installed on your computer, you normally need not un-install it; installing the current version will replace the older version.
Download TQSL 2.3 for Windows here .
Troubleshooting while upgrading from TQSL version 1.x