“As of 1400 UTC on January 16, ARRL Logbook of The World (LoTW) no longer will accept contacts that have been digitally signed by versions of TQSL earlier than version 2.0. Users of earlier versions are encouraged to upgrade as soon as possible, as older TQSL versions contain uncorrected defects and display inaccurate error messages."[ 1 ]
TQSL for MacOS and Microsoft Windows may be installed from the LoTW Installing or Upgrading TQSL page.
TQSL source code for Linux, and other unix-like operating systems, is available from the Installing or Upgrading TQSL page. Prepackaged versions of TQSL (both binary and source) may be available through your Operating System (or “distribution") package management system.
[ 1 ] “https://twitter.com/arrl/status/816668087227445249", ARRL The national association for Amateur Radio, last modified January 3 2017, http://www.arrl.org/news/logbook-of-the-world-to-no-longer-accept-contacts-signed-by-tqsl-versions-earlier-than-2-0-1.