Nagios 3.2.0 has just been released and can be downloaded from:
Several bugs were fixed since the 3.1.2 release, including a fix for incorrect next service check time calculation when Nagios is reloaded with different timeperiod ranges. Please note that there is a known issue regarding check scheduling with timeperiod exceptions. Read the "Known Issues" page (newly added) of the online documentation for moreinfo on this.
Here are the changes since 3.1.2:
3.2.0 - 08/12/2009