On occasion, SAP renews its domain certificates for "*.sapbydesign.com" and sends a communication out advising to check and possibly renew any certificates for integrations or add-ons.
Navigator integrations and add-ons do not use certificates to authenticate so no action is necessary for them. However, it is recommended to check through your arrangements under "Application and User Management - Communication Arrangements" to verify none being used are set up to authenticate with certificates.
Note that arrangements with a blank communication type and are pre-defined out of the box aren't commonly used. However, if they are in use their certificates may need to be updated in non-Navigator middleware:
We can't advise on if your organization is using those integrations or not, but the vast majority of Navigator customers do not use them. IConnect does not use those arrangements.
Be aware that while a communication arrangement may have the drop-down for authentication set to "SSL Client Certificate" it doesn't mean a certificate is always being used. With that option selected a username/password can still be maintained so basic authentication might still be in effect.