George Rawlinson authored Mar 16, 2021 and Frederik Schwan committed Mar 19, 2021

According to upstream documentation[0], the configuration parameter
smtpd_tls_dh512_param_file will be ignored from the next release of
Postfix (3.6).

[0]: http://www.postfix.org/postconf.5.html#smtpd_tls_dh512_param_file