According to Foresight News: Privacy-focused browser Tor has announced the implementation of a Proof-of-Work (PoW) defense for Onion Services with the release of Tor 0.4.8. The defense aims to prioritize verified network traffic in order to deter denial-of-service (DoS) attacks. Tor's PoW defense is a dynamic and reactive mechanism that remains dormant under normal usage conditions, ensuring a seamless user experience. However, when Onion Services face pressure, the mechanism prompts incoming client connections to perform a series of more complex operations. Tor advises users to update their Onion Services to version 0.4.8.