Hi,
Great that ESP8266 (almost) supports SSL and emoncms.org is superb
but not so good that every 90 days the fingerprint has to be manually updated on ESP8266 nodes.
Why not modify the SSL cert install procedure to get the cert a week early but not install and provide an api call that details the change date for the SSL cert, new fingerprint and perhaps the next expiry. That way simple ESP8266 nodes could keep going without manual intervention.