Let’s Encrypt is moving from a cross signature with IdenTrust to a root cert of their own. This new cert chain is accepted by most software but only two thirds of android users. More details here: https://letsencrypt.org/2020/11/06/own-two-feet.html.
Will Render keep using DST Root X3 until September 2021 or switch to the certificate chain that leads to ISRG Root X1 on January 11, 2021 (as would be the default)?