Many existing PKI systems may rely on outdated or legacy interfaces, making them less compatible with modern applications and technologies. This can hinder interoperability with newer systems, limit integration capabilities, and potentially expose security vulnerabilities as these interfaces may not adhere to current security standards.

Some PKI systems might be limited to traditional or classic cryptographic algorithms, which may not provide the same level of security as more modern alternatives with quantum-cryptography support. This limitation could render the PKI system vulnerable to emerging cryptographic threats and compromise the overall security posture.

User interfaces or dashboards that are not intuitive, visually appealing, or user-friendly. This can impact the user experience and the efficiency of administrators in managing the PKI system. A lack of user engagement may also contribute to oversight or errors.