Nokia Cloud Software Group Holdings, Inc. This document provides guidance for migration from traditional digital signature algorithms to post-quantum cryptographic (PQC) signature algorithms. It compares three models under discussion in the IETF for PKI-based protocols: composite certificates, dual certificates, and PQC-only certificates. The goal is to help operators and engineers working on cryptographic libraries, network security, and PKI/key management infrastructure select an approach that balances interoperability, security, and operational efficiency during the transition to post-quantum authentication.