Change in the format of serial numbers of certificates issued by I.CA
From August 25, 2025, there will be a change in the format of serial numbers (Serial Number – SN) for certificates issued by I.CA. All serial numbers will now be longer – in accordance with the requirements of international standards.
Why is the change taking place?
As a trusted certification authority, I.CA is part of the Microsoft Trusted Root Certificate Program (MTRCP). This program emphasizes compliance with current security and technical standards, including ETSI TS 119 411-6 and the so-called S/MIME Baseline Requirements.
What does the change mean for users?
From August 25, 2025, all newly issued I.CA certificates will contain a longer serial number.
Therefore, we recommend testing these new certificates in your environment in a timely manner to avoid any complications during their deployment.
- You can get a free test certificate at: https://www.ica.cz/en/testing
If you have any questions, please do not hesitate to contact us on our hotline +420 284 081 930 or at podpora@ica.cz.
