I don't know if this helps you. I have just raised a support ticket with Apple regarding this. I have noticed that Apple have not changed the certificates for the Sandbox environment yet. That was set to happen weeks ago and we only have 8 days before the production is changed.

I don't know if this helps you but I have just opened a support ticket because the sandbox APN has not changed its certificate. I'm connecting in the UK and getting an Apple Public Server RSA CA not one linked in the emails sent by Apple.

Correcting myself. The certificate Apple are sending is an intermediate that chains back to UserTrust and I think that is in the email they have sent. Apologies for any red herring there.

Correcting myself. The certificate Apple are sending is an intermediate that chains back to UserTrust and I think that is in the email they have sent. Apologies for any red herring there.