Let’s Encrypt Support for Android 7 Has Ended

Google Cloud Nightscout » Let’s Encrypt and Android 7

Google Cloud Nightscout uses Let’s Encrypt. Unfortunately, free support for Android 7 has ended, as described here. If you try to access a Google Cloud Nightscout site using Android 7 or older, it will fail. Devices running newer versions will continue to work fine.

You may see the following error on your uploader:
javax.net.ssl.SSLHandshakeException: Java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.

In the case of a follower app or web browser, you may see a message like:
... can't open the page.

To access your site, use a device running Android 8 or newer.