Signal has introduced Sparse Post-Quantum Ratchet (SPQR), a new cryptographic mechanism designed to enhance resistance against quantum computing attacks by integrating post-quantum key encapsulation with its existing double ratchet system. This hybrid 'Triple Ratchet' approach ensures forward secrecy and post-compromise security, with formal verification and continuous validation underpinning its implementation. The rollout will be gradual and backward compatible, requiring users only to keep their clients updated.