Router's connect_timeout configuration option was measured in milliseconds instead of seconds in v2.1.5. (Bug #27597561, Bug #89740)

Router's max_connect_errors option did not function in v2.1.5. (Bug #27559218, Bug #89700)

On Windows, the returned POLLHUP returned by WSAPoll() was not handed properly. This caused high CPU utilization after several opened/closed connections. (Bug #27532709)