This is unsupported, please upgrade using the same package installer as Syslog-ng PE was installed with.
NOTE: The .run installer is no longer available, if Syslog-ng PE was installed using the .run installer please take a backup of the /opt/syslog-ng/etc and /opt/syslog-ng/var directories, uninstall Syslog-ng, and then re-install using the package desired.
Once the new version is installed, you can replace the contents of the /opt/syslog-ng/etc and /opt/syslog-ng/var directories if needed.
Restart the Syslog-ng service to pick up previous settings, license, certificates, etc...
Please see the following section in the Syslog-ng PE admin guide for more information:
https://support.oneidentity.com/technical-documents/syslog-ng-premium-edition/7.0.20/administration-guide/15#TOPIC-1434882
*NOTE* - If using an .rpm to upgrade and an .rpm was used previously, yet the errors still occur, please ensure the proper command is used for upgrading (see below):
rpm -Uvh insert_syslog-ng_rpm_package_here