- Moved to C++ 2011, a cleaner more powerful version of C++ that has allowed us to [improve the quality of implementation](http://bert-hubert.blogspot.nl/2015/01/on-c2011-quality-of-implementation.html) in many places.
- Implemented dedicated infrastructure for dealing with DNS names that is fully "DNS Native" and needs less escaping and unescaping
- Switched to binary storage of DNS records in all places
-- Moved ACLs to a dedicated Netmask Tree (Patricia Trie)
+- Moved ACLs to a dedicated Netmask Tree
- Implemented a version of [RCU](https://en.wikipedia.org/wiki/Read-copy-update) for configuration changes
- Instrumented our use of the memory allocator, reduced number of malloc calls substantially.
- EDNS Client Subnet support in PowerDNS Recursor (authoritative has had this for years)
- Lua asynchronous queries for per-IP/per-domain status
- Caches that can now be wiped per whole zone instead of per name
+- Statistics on authoritative server response times (split for IPv4 and IPv6)
+- APIs are no longer marked as 'experimental' and had one final URL change
+- New metric: tcp-answer-bytes to measure DNS TCP/IP bandwidth
.. to be continued