Post 2.3 changes:

* TCP and UDP now done by the same process/service (2.4.01)

* upstream_servers now a full "dictionary" variable (2.4.02, 2.4.03)

* Full DNS compression and decompression support (2.4.04)

* RR rotation and TTL aging (2.4.05)

* ip_blacklist support (2.4.06)

* execfile support (2.4.07)

* Merging multiple identical in-flight queries (2.4.07)

* Deadwood 2.4 marked stable (2.4.08)

* Default DNS servers are Google's DNS servers (2.4.09)

* filter_rfc1918 parameter added (2.5.01)

* infrastructure to process DNS packets from non-recursive servers (2.6.01)

* non-glueless recursion (2.6.02)

* NS glueless recursion (2.6.03)

* Recursion with incomplete CNAME records (2.6.04)

* Recursion with ANY records (2.6.05)

* reject_aaaa ; feature-complete testing release (2.9.01)