Recently we have seen that some standard CA’s certificates (Entrust, Telekom) are expiring from our landscape & that certificates are not even use in any functionality.
There is an standard SAP note, which explain whether you need to renew the same or not.
2776722 – Expiring CA’s certificates
if you want to renew the same then there is an website mentioned in this note & SAP clearly mentioned below –
The updated certificates must be acquired from the CA’s and must be downloaded from their official website, it is the customer’s responsibility to align with the vendor to download the correct certificate(s).