Security Certificate Upgrades to api.authorize.net

[KiranK]

Hello,

I am using account in production mode. I haven't yet updated the certificate referring:

https://community.developer.authorize.net/t5/The-Authorize-Net-Developer-Blog/Production-Certificate...

Payments on site are going fine, except 2-3 cases of empty response from api for CIM.

Do we need to update the certificate? if yes, from where to download .pem file?

Thanks,

Kiran

[KiranK]

I am using PHP SDK and the location of .pem file is

[initial path to authnet folder]/lib/ssl/cert.pem

Is any other file to be added extra or only update to above file is required?