Stratum V2 and DATUM are both protocols designed to improve communication and efficiency in cryptocurrency mining, but they serve different purposes and operate at different layers of the mining ecosystem.

Stratum V2 is an upgrade to the original Stratum protocol, used for communication between miners and mining pools. It enhances security, reduces data transfer, and allows miners to choose their block templates (a feature called Job Negotiation), improving decentralisation. Stratum V2 also encrypts communication, protecting against man-in-the-middle attacks, and offers better efficiency for large-scale operations by reducing bandwidth usage.

DATUM (Decentralised, Autonomous Trustworthy Universal Mining) is a broader protocol concept that focuses on fully decentralised mining infrastructure. Unlike Stratum V2, which still depends on mining pools, DATUM aims to eliminate central coordination by enabling autonomous job assignment among miners. This makes it more resistant to pool-level censorship or manipulation, promoting true decentralisation.

In summary, Stratum V2 improves existing mining pool systems, making them more secure and efficient, while DATUM aims to remove the need for mining pools entirely, fostering a fully decentralised mining environment. Both seek to enhance the Bitcoin network but differ in scope—Stratum V2 modernises, DATUM revolutionises.