####syslog-ng --fd-limit 8192

WARNING: Configuration file format is too old, syslog-ng is running in compatibility mode Please update it to use the syslog-ng 3.5 format at your time of convinience, compatibility mode can operate less efficiently in some cases. To upgrade the configuration, please review the warnings about incompatible changes printed by syslog-ng, and once completed change the @version header at the top of the configuration file.;

WARNING: global: the default value of log_fifo_size() has changed to 10000 in syslog-ng 3.3 to reflect log_iw_size() changes for tcp()/udp() window size changes;

Using a global log-fetch-limit() option was removed, please use a per-source log-fetch-limit();

WARNING: window sizing for tcp sources were changed in syslog-ng 3.3, the configuration value was divided by the value of max-connections(). The result was too small, clamping to 100 entries. Ensure you have a proper log_fifo_size setting to avoid message loss.; orig_log_iw_size='0', new_log_iw_size='100', min_log_fifo_size='1300000'

and I am unable to  stop the syslog-ng service using systemctl, it immediately re-starts, I am using centOS 7.2, I have noticed few other people on the internet had the same problem, please advice, any help is appreciated.