In 2.1.0 I've added the ability to fallback to various public servers if the main p2pd.net servers are down. I added this feature because it makes the software much more resilient. If any of the services go down I don't have to worry about the entire program breaking and having to build rock-solid monitoring features.
Version 2.1.0 also includes multiple bug fixes. I've created a new service on p2pd.net for showing port mappings, testing port forwarding, and sending basic hello packets to a host. The last feature was necessary to test whether a TURN relay was working as recent versions of Coturn seem to now prohibit setting up a permission for your own IP + port mapping in order to test the TURN client. The TURN server version on p2pd.net doesn't have this limitation for now though.
Another important change in this version is adding multiple routes to use for signalling messages to the peer address format. If the main route is down additional routes can be used as a backup. To avoid wasting too much bandwidth there are currently 2 routes for now. Finally, I have changed the way the clock skew calculations work to load balance across multiple NTP servers. The current code that eliminates outliers is still used but the code now has retries to counteract packet-loss in the underlying UDP protocol. This should be much less spammy for NTP server owners.
When time permits I'd like to double the number of tests and develop a new way to test network services. This should make reaching 90% coverage more a feature than a grind.