v2.1.8

This version introduces uptime-based routing, proposed in NKP-0021. The uptime and latency will be used together to compute an effective latency, resulting in a routing rule that prefers neighbors with lower latency (fast) and higher uptime (stable).

This is the initial implementation of NKP-0021. The curve and parameters are subject to change in later versions while we collect more data and feedbacks of this version.