Flutter - Android 7 CERTIFICATE_VERIFY_FAILED with LetsEncrypt SSL cert after Sept 30, 2021

After Sept 30, 2021, https get/post requests to a website using a Let’s Encrypt SSL certificate on an old Android 7 device were failing with this error: HandshakeException: Handshake error in client (OS Error: CERTIFICATE_VERIFY_FAILED: certificate has expired(handshake.cc:354))

Solution

In Flutter, to once again make SSL https connections on older devices to Let’s Encrypt SSL protected websites, we can supply Let’s Encrypt’s trusted certificate…