Versions 2.1.1 and 2.2.0 were released yesterday. Full details and download links available at: http://gdnsd.org/
Notable new features in 2.2.0 include MaxMind GeoIP2 support for the geoip plugin (via libmaxminddb), NAT64 address range support for v6->v4 translations, flushable stats fetches over http, and some security enhancements on Linux (PR_SET_NO_NEW_PRIVS on kernels 3.5+, and more-secure defaults in the shipped systemd unit file).
2.1.1 is a backport onto the 2.1.0 code of some recent master-branch bugfix work that occured during the run up to 2.2.0. It only the fixes that seemed low-risk and/or high-reward, and should be a drop-in replacement for 2.1.0 (or a good reference for vendor-patching any of these issues in a 2.1.0-based distro package).