[schoen]

An easier way for an Android end-user or an administrator of a small number of Android devices to deal with this is to switch from the built-in browser to Firefox Mobile, because it comes with its own root store which includes the ISRG root, even on an OS that doesn't know about that.

(This suggestion is provided in the ISRG post about this change -- https://letsencrypt.org/2020/11/06/own-two-feet.html#if-you-... -- and elsewhere on the Let's Encrypt community forum. If the IdenTrust root expiration ends up leading to much consternation among users and site operators, this might be good information to spread around more widely!)