This is the initial stable release of rsyslog v6. It is basically the last beta version plus some more fixes. This version provides functional and performance enhancements, for example the Hadoop (HDFS) support has been considerably speeded up by supporting batched insert mode. Also, TCP transmission overhead for TLS has been dramatically improved. TCP now also supports input worker thread pools. Most importantly, rsyslog now supports log normalization via liblognorm rule bases. This permits very high performance normalization of semantically equal messages from different devices (and thus in different syntaxes).
Note that config scoping, available in the beta versions, is NOT supported by v6-stable. This was decided because it would have been functionality equivalent to the new config language upcoming in v6.3 (already available as part of the devel version). As scoping was not available in any earlier versions, introducing it in v6.2 would have added, in the long term, just another method of doing some identicaly thing via the ugly old config language. This would have lead to user confusion and more complex than necessary code. If you are interested in the cleaner config language, we strongly encourage you to have a look at rsyslog 6.3.
With the arrival of the stable v6 version, version 4 will be retired and is no longer officially supported (but support is provided under maintenance contracts, of course).
As always, feedback is appreciated.