After further investigation with the OP, this is the situation...
We recently updated our SSL/TLS certificates to comply with new security and certificate authority requirements. The new certificates use a newer root certificate that older iPads (on older iOS versions) and other legacy devices don’t recognize or trust. All internet web sites will have to do this.
Because there are older devices that can no longer be updated, they can’t get the newer SSL security roots it needs to connect to our servers. That’s why some apps or devices with ancient browsers stopped working. Unfortunately, there isn’t a safe way for us to downgrade security globally just for a handful of older devices.
Hope this helps explain things. It's an internet-wide issue and the overall situation with supporting legacy devices will become worse, not better.
Dave
