Definition
Version rolling is a mining technique that treats reserved bits of the block header's nVersion field as an additional source of variation. By cycling through allowed version bits, hardware effectively multiplies the search space it can explore per nonce range, which is the mechanism behind overt ASICBoost. Standardizing how miners and pools agree on which bits may be rolled is the job of BIP 310.
What BIP 310 actually defines
Authored by Pavel Moravec and Jan Capek in March 2018, BIP 310 introduces a generic extension-negotiation framework for the Stratum protocol via a mining.configure message. Its flagship extension is version-rolling: the miner advertises a mask of bits it wants to change and a minimum bit count, and the server replies with the intersection of bits it permits. From then on, share submissions carry a version_bits value. This solved a real gap, because the original Stratum protocol had no way for a miner to communicate a changed block version back to the server.
BIP 310 versus BIP 320
BIP 310 negotiates the mechanism; BIP 320 defines which sixteen header bits (positions 13 to 28) are reserved for general use and masked out of soft-fork signaling. Together they let version rolling coexist safely with future protocol upgrades. The two specifications grew directly out of the industry's move to make ASICBoost overt and detectable on-chain.
For the efficiency trick this enables, read our ASICBoost entry; for the protocol carrying the negotiation, see Stratum V1.
In Simple Terms
Version rolling is a mining technique that treats reserved bits of the block header’s nVersion field as an additional source of variation. By cycling through…