2018-08-03: changed snmp scan function
2018-08-13: code cleanup, add metrics
2020-06-08: changed snmp-scan function
2021-09-06: rewritten for CMK 2.0
2021-09-07: added WATO for check and discovery function
            renamed from checkpoint_vsx to checkpoint_vsx_system
2021-09-21: changed graph definition for packets graph to stack
2021-09-24: changed graph definition for connections graph to make it scale with 
            the active connections (suggested by raulcurro[at]gmail[dot]com) 
            moved Main IP to details, if it is not an IPv4 address            
2022-10-23: fixed warning in upgrade "non-empty params vanished" for policyname and ha_state

2023-05-29: moved gui files to ~/local/lib/check_mk/gui/plugins/...
2023-06-17: added support for predicted levels for connections active
            changed bytes/packets/logs metrics to check_levels/check_levels_predictive
            changed upper/lower levels for active connections to levels (predictive)
            added wato levels option for bytes/packets/logs perf counters
2023-06-18: cleanup variable names to better meet python standards
            moved wato file to check_parameters sub directory
2023-06-19: some refactoring (VsXMetrics class)