This is a bugfix release.
The handling of the case where there are many hosts that may not be resolved by the system DNS server has been fixed. Previously the monitoring service might experience performance degradation in such a case. This issue affected only release 4.0.8716.
State condition checking for the SNMP monitors of type “delta” has been fixed. Previously, an actual poll result was checked, not a delta between two polls that is stored as a performance value for such monitors. Besides, such monitors now remain in a steady “down state” when polling fails; previously they might switch between “down” and “unknown” states. This issue affected only earlier 4.0 releases.