Antminer X9
Monero ASIC Miner
1000KH
HASHRATE
2.47W/KH
EFFICIENCY
2470W
POWER
£861.31
EST. MONTHLY
205
DAYS
EST. ROI
This guide explains BIP 135 version bits in plain English. It covers the problem behind the BIP, why it matters and whether the proposal is part of Bitcoin today.
TL;DR
- What it is: BIP 135 proposed generalising BIP 9 version-bit signalling so each deployment could configure its threshold, window size, minimum locked blocks and minimum locked time. It retained the familiar state machine while extending it to arbitrary consensus changes.
- Why it matters: BIP 135 explored a flexible activation state machine but is a closed proposal. Its main lesson is that configurable thresholds demand explicit parameters, independent state verification and careful language about what signalling represents.
- Current position: The informational BIP is Closed and did not replace BIP 9 in Bitcoin consensus.
BIP 135 version bits in simple English
BIP 135 version bits: Miner version bits reveal block-production signals under defined rules. They do not measure users, economic nodes or moral legitimacy.
Simple example
A node operator is checking BIP 135 version bits. Flexible values could model faster or slower coordination. Calling the mechanism voting can overstate what a hash-power threshold decides.
Key terms in plain English
- BIP:
- Bitcoin Improvement Proposal: a document describing a proposed rule, standard or process. Its status must be checked separately.
- Bitcoin Core:
- Widely used software that validates Bitcoin and can provide wallet, network and operator tools.
- Consensus:
- The shared rules full nodes use to decide whether blocks and transactions are valid.
- Soft fork:
- A proposed tightening of Bitcoin rules that old nodes may not enforce themselves.
- Node:
- A computer running Bitcoin software that checks data and communicates with other peers.
Parameters added
Beyond name, bit, start time and timeout, the proposal added deployment-specific threshold, window size, minimum locked blocks and minimum locked time. Flexible values could model faster or slower coordination. Every node would need identical parameters to calculate the same activation state.
State-machine continuity
DEFINED, STARTED, LOCKED_IN, ACTIVE and FAILED concepts were retained with extended transition conditions. Boundary calculations depend on prior-window state, median-time-past and block counts. Tests need genesis-adjacent cases, delayed starts, exact thresholds and reorganisations.
Signalling is not voting authority
Miner version bits reveal block-production signals under defined rules; they do not measure users, economic nodes or moral legitimacy. Calling the mechanism voting can overstate what a hash-power threshold decides. Deployment design must specify enforcement and compatibility separately.
Arbitrary fork scope
The proposal discussed signalling beyond backwards-compatible soft forks. A hard fork cannot become compatible merely because a bit threshold is reached; old validators still reject new rules. Interfaces must state the rule change and consequences, not show one generic approval percentage.
Lock-in grace controls
Minimum locked blocks and time could provide a deployment grace period independent of the signalling window. More flexibility also creates more parameter combinations, operator confusion and implementation divergence. A small configuration error can shift activation height across nodes.
Closed status
BIP 135 is not current Bitcoin activation policy. Historical clients or alternative chains may have implemented variants, but that does not alter Bitcoin Core consensus. Research environments should pin chain parameters and prevent accidental connection to production networks.
Simulation and monitoring
Generate signalling patterns just below, at and above threshold across variable windows, then reorganise around every transition. Compare two independent implementations and expose the complete parameter set in monitoring. A status label without the calculation inputs is inadequate evidence.
Frequently asked questions
What is the main point of BIP 135 version bits?
BIP 135 version bits: Miner version bits reveal block-production signals under defined rules. They do not measure users, economic nodes or moral legitimacy.
For BIP 135 version bits, what should a beginner know about parameters added?
Beyond name, bit, start time and timeout, the proposal added deployment-specific threshold, window size, minimum locked blocks and minimum locked time.
For BIP 135 version bits, what should a beginner know about state-machine continuity?
DEFINED, STARTED, LOCKED_IN, ACTIVE and FAILED concepts were retained with extended transition conditions.
For BIP 135 version bits, what should a beginner know about signalling is not voting authority?
Miner version bits reveal block-production signals under defined rules. They do not measure users, economic nodes or moral legitimacy.
Conclusion
BIP 135 explored a flexible activation state machine but is a closed proposal. Its main lesson is that configurable thresholds demand explicit parameters, independent state verification and careful language about what signalling represents.
Primary sources
Check the current specification status and the documentation for the exact implementation you operate before moving production funds or changing a mining node.
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