Conditional buffering in 1.4.764

Version 1.4.764 has been released.
size(), replace() and substr() functions are now available for string manipulation. Also added buffer_size() and buffer_count() functions to the pm_buffer module. This allows conditional buffering, see the Explicit drop section in the reference manual and this mailing list post about how this can be used.
Some other issues and bugs were fixed, details are in the ChangeLog.

More log rotation

nxlog v1.4.712 has been released.
The most notable addition in this release is a new extension module xm_fileop which adds support for file operations. This allows more sophisticated log rotation which can be used also for nxlog's own logs.
See the full ChangeLog in the sources for the list of all enhancements and fixes included in this release.

Graylog2 GELF support added

I've added GELF output support to nxlog in version 1.4.624.
Now with this enhancement it is possible to collect logs from several platforms and sources and to forward it to graylog2 in GELF format so that the structured data is preserved and is available for search and analytics. The most notable source is probably Windows EventLog (from XP to W7) as you were requesting this, but I should note that there is a lot more that you can do with it.