After upgrading syslog-ng, the following warning may be shown on the system logs as well as in the output of "systemctl status syslog-ng"
WARNING: Your configuration file uses an obsoleted keyword, please update your configuration; keyword='pass_unix_credentials', change='The use of pass-unix-credentials() has been deprecated in syslog-ng 3.35 in favour of the \'so-passcred()\' source option or the \'ignore-aux-data\' source flag', location='/opt/syslog-ng/etc/syslog-ng.conf:64:5'
This WARNING message is about the plugin.conf file located in the wec directory.
The plugin.conf file includes the following line:
unix-dgram("`unix_domain_socket`" flags(no-parse) pass_unix_credentials(no) `__VARARGS__`);