mining: add coinbase locktime, sequence and version fields to getblocktemplate RPC #34419

1. 
   Sjors commented at 2:17 pm on January 27, 2026: member

   • BIP54 proposes contraining the cointbase transaction nLockTime and nSequence fields. Our internal mining code has been doing this since #32155, but currently the fields are only communicated to IPC clients (see e.g. #33819).

   • Additionally this PR adds the nVersion field. This is unrelated to BIP54, but it means getblocktemplate now covers all coinbase transaction fields.

   Typically adding new fields to the getblocktemplate involves a BIP, so I’ll keep this in draft while I write one. WIP: https://github.com/Sjors/bips/pull/1

2. refactor: use CoinbaseTx for coinbasevalue a73c41a1dc
3. DrahtBot added the label Mining on Jan 27, 2026
4. 
   DrahtBot commented at 2:17 pm on January 27, 2026: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/34419.

   Reviews

   See the guideline for information on the review process. A summary of reviews will appear here.

5. mining: add coinbase locktime and sequence fields

   Expand the getblocktemplate RPC result with two fields to prepare
   for a possible BIP54 deployment in the future.

   90025e8597
6. Sjors force-pushed on Jan 27, 2026
7. mining: add coinbase_version field to GBT faa8b518fe
8. DrahtBot added the label CI failed on Jan 27, 2026
9. 
   Sjors commented at 3:03 pm on January 27, 2026: member

   Added the coinbase nVersion.
10. Sjors renamed this:
    mining: add coinbase locktime and sequence fields to getblocktemplate RPC
    mining: add coinbase locktime, sequence and version fields to getblocktemplate RPC
    on Jan 27, 2026
11. DrahtBot removed the label CI failed on Jan 27, 2026

Contributors
Sjors DrahtBot

Labels
Mining