Hi,
please check here: https://www.postgresql.org/docs/10/progress-reporting.html
It only shows 9.6, 10 and 11 as "Supported Versions" on the top of the page.
==> Supported Versions: Current<https://www.postgresql.org/docs/current/progress-reporting.html> (11<https://www.postgresql.org/docs/11/progress-reporting.html>) / 10<https://www.postgresql.org/docs/10/progress-reporting.html> / 9.6<https://www.postgresql.org/docs/9.6/progress-reporting.html>
Regards
Daniel