We have updated the Adafruit IO SSL/TLS certificate. If you are having issues connecting, please ensure you have the latest Adafruit IO Arduino library version by navigating to the Arduino Library Manager (from the Arduino IDE, navigate to: Sketch -> Include Library -> Manage Libraries):


The certificate is fingerprinted in that library and you will have issues connecting if that library is out of date. The current version with the latest fingerprint is 3.7.0. There also an example that was updated in the Adafruit MQTT Library, we’ve updated this library too.

If you are using an ATWINC1500 module, you’ll need to update the certificate built into the module. Please follow these instructions on this Learning System Guide for step-by-step instructions…

In the future, we will announce this much further in advance to ensure everyone is aware of the scheduled certificate updates to reduce downtime. The next update will be in approximately 2 years.

If you had any significant downtime or are having issues getting connected again, please reach out to us and we can assist you.