Stratum V2

Stratum V2 is an upgraded version of the protocol that coordinates communication between bitcoin miners and mining pools. It replaces Stratum V1, in use since 2012, with an encrypted binary protocol and, most significantly, an optional feature called job declaration that lets individual miners choose which transactions go into the blocks they work on.

Why it matters

Under Stratum V1, the pool constructs the block template, so a handful of large pools effectively decide which transactions the network confirms. With a majority of hashrate often coordinated by just a few pools, that concentration is bitcoin's most cited centralization risk, since pools could be pressured to exclude transactions from sanctioned addresses or to signal for protocol changes their miners do not support. Stratum V2's job declaration returns transaction selection to the individual miner while the pool still aggregates payouts, and its encryption prevents hashrate hijacking attacks that plaintext V1 permits. Development has been driven by the open Stratum V2 Reference Implementation project along with mining firms such as Braiins, and adoption is gradual because pools, firmware, and miners must all upgrade.

In the gold vs bitcoin debate

Censorship resistance is a core bitcoin claim, and Stratum V2 exists to keep it true as mining industrializes. Gold has its own chokepoints, with a small set of accredited refiners and clearing banks standing between most owners and the market. Both monetary systems face the same pattern, decentralized assets flowing through centralizing infrastructure, and Stratum V2 is bitcoin's engineering answer to it.