kernel: Chainparams and headerssync updates pre-31.0

achow101 commented at 0:33 am on February 26, 2026: member

Update chainparams and headerssync params per the release process.

Also added new assumeutxo snapshots for each network. I’ve uploaded snapshots to https://achow101.com/files/utxo-snapshots/

kernel: update assumed blockchain and chainstate sizes 5ca0c55517

kernel: update defaultAssumeValid and minimumChainWork 8eaf1d26d4

kernel: update chainTxData cf261b071f

kernel: Update headerssync params 58c2e23fca

DrahtBot added the label Validation on Feb 26, 2026

achow101 renamed this:
~~kernel: Chainparams and headerssync updates~~
kernel: Chainparams and headerssync updates pre-31.0
on Feb 26, 2026

achow101 added this to the milestone 31.0 on Feb 26, 2026

DrahtBot commented at 0:34 am on February 26, 2026: contributor

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

Reviews

See the guideline for information on the review process.

Type	Reviewers
ACK	janb84, Sjors, sipa, jaonoctus, fjahr

If your review is incorrectly listed, please copy-paste <!–meta-tag:bot-skip–> into the comment that the bot should ignore.

Conflicts

Reviewers, this pull request conflicts with the following ones:

#26201 (Remove Taproot BIP 9 deployment by Sjors)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

LLM Linter (✨ experimental)

Possible places where named args for integral literals may be used (e.g. func(x, /*named_arg=*/0) in C++, and func(x, named_arg=0) in Python):

[datetime(2028, 10, 10)] in contrib/devtools/headerssync-params.py

2026-02-26 07:23:28

kernel: Add recent assumeutxo snapshot info 44538f8ada

janb84 commented at 1:21 pm on February 26, 2026: contributor

ACK 44538f8ada868cb73ffa7a4bfb5267046d3f6b85

Checked some hashes with block heights /chainwork / getchaintxstats, all match (for mainnet. testnets checked only public information)

Mainnet: https://mempool.space/block/00000000000000000000ccebd6d74d9194d8dcdc1d177c478e094bfad51ba5ac => 938'343

MinimumChainwork matches:

0bitcoin-cli getblockheader 00000000000000000000ccebd6d74d9194d8dcdc1d177c478e094bfad51ba5ac
1{
2  "hash": "00000000000000000000ccebd6d74d9194d8dcdc1d177c478e094bfad51ba5ac",
3  "height": 938343,
4[...]
5  **"chainwork": "0000000000000000000000000000000000000001128750f82f4c366153a3a030"**,
6}

https://mempool.space/block/0000000000000000000147034958af1652b2b91bba607beacc5e72a56f0fb5ee = > 935'000

getchaintxstats match ;

 0bitcoin-cli getchaintxstats 4096 00000000000000000000ccebd6d74d9194d8dcdc1d177c478e094bfad51ba5ac
 1{
 2  "time": 1772055173,
 3  "txcount": 1315805869,
 4  "window_final_block_hash": "00000000000000000000ccebd6d74d9194d8dcdc1d177c478e094bfad51ba5ac",
 5  "window_final_block_height": 938343,
 6  "window_block_count": 4096,
 7  "window_interval": 2346169,
 8  "window_tx_count": 12671917,
 9  "txrate": 5.40111006496122
10}

Testnet 3

https://mempool.space/testnet/block/000000007a61e4230b28ac5cb6b5e5a0130de37ac1faf2f8987d2fa6505b67f4 => 4'842'348

https://mempool.space/testnet/block/00000000000000f4971a7fb37fbdff89315b69a2e1920c467654a382f0d64786 => 4'840'000

Testnet 4

https://mempool.space/testnet4/block/0000000002368b1e4ee27e2e85676ae6f9f9e69579b29093e9a82c170bf7cf8a => 123'613

https://mempool.space/testnet4/block/000000000bd2317e51b3c5794981c35ba894ce27d3e772d5c39ecd9cbce01dc8 => 120'000

Signet

https://mempool.space/signet/block/00000008414aab61092ef93f1aacc54cf9e9f16af29ddad493b908a01ff5c329 => 293'175

https://mempool.space/signet/block/0000000577f2741bb30cd9d39d6d71b023afbeb9764f6260786a97969d5c9ac0 => 290'000

in src/kernel/chainparams.cpp:410 in 44538f8ada

402@@ -391,20 +403,26 @@ class CTestNet4Params : public CChainParams {
403                 .hash_serialized = AssumeutxoHash{uint256{"784fb5e98241de66fdd429f4392155c9e7db5c017148e66e8fdbc95746f8b9b5"}},
404                 .m_chain_tx_count = 11347043,
405                 .blockhash = uint256{"0000000002ebe8bcda020e0dd6ccfbdfac531d2f6a81457191b99fc2df2dbe3b"},
406+            },
407+            {
408+                .height = 120'000,
409+                .hash_serialized = AssumeutxoHash{uint256{"10b05d05ad468d0971162e1b222a4aa66caca89da2bb2a93f8f37fb29c4794b0"}},
410+                .m_chain_tx_count = 14141057,

jaonoctus commented at 7:09 pm on February 27, 2026:

m_chain_tx_count seems to be wrong. Is this a typo?

0-.m_chain_tx_count = 14141057,
1+.m_chain_tx_count = 13870119,

$ bitcoin-cli gettxoutsetinfo hash_serialized_3

0{
1  "height": 120000,
2  "bestblock": "000000000bd2317e51b3c5794981c35ba894ce27d3e772d5c39ecd9cbce01dc8",
3  "txouts": 13870119,
4  "bogosize": 1142705000,
5  "hash_serialized_3": "10b05d05ad468d0971162e1b222a4aa66caca89da2bb2a93f8f37fb29c4794b0",
6  "total_amount": 5999799.97251533,
7  "transactions": 9181935,
8  "disk_size": 1023009172
9}

achow101 commented at 7:51 pm on February 27, 2026:

No, it is correct. It’s the count of transactions in the chain, not the number of UTXOs.

jaonoctus commented at 8:25 pm on February 27, 2026:

@achow101 Oh I see, it should match txcount from getchaintxstats instead. Pardon

In that case, it seems to be right then.

$ bitcoin-cli getchaintxstats 4096

0{
1  "time": 1769234583,
2  "txcount": 14141057,
3  "window_final_block_hash": "000000000bd2317e51b3c5794981c35ba894ce27d3e772d5c39ecd9cbce01dc8",
4  "window_final_block_height": 120000,
5  "window_block_count": 4096,
6  "window_interval": 2168096,
7  "window_tx_count": 56313,
8  "txrate": 0.02597348087907547
9}

jaonoctus commented at 7:11 pm on February 27, 2026: none

[REDACTED]

jaonoctus commented at 9:46 pm on February 27, 2026: none

I’ve validated the new chainparams and headerssync against my own nodes. I’ll be hosting the new torrent snapshot files at https://bitcoin-snapshots.jaonoctus.dev once this PR is merged.

mainnet

m_assumeutxo_data @ 935'000
chainTxData @ 935'000
consensus.nMinimumChainWork @ 938'343
consensus.defaultAssumeValid @ 938'343

0magnet:?xt=urn:btih:3492d082655d173d3459f7a5e454f3dd4ed0101b&dn=utxo-935000.dat&tr=udp%3A%2F%2Ftracker.bitcoin.sprovoost.nl%3A6969&tr=udp%3A%2F%2Ftracker.opentrackr.org%3A1337%2Fannounce

sha256: e572ddbe456d254f05fb004cebe225bdb3656074b66f0e9b1c7fa83e1301d486

0$ sha256sum utxo-935000.dat
1e572ddbe456d254f05fb004cebe225bdb3656074b66f0e9b1c7fa83e1301d486

0$ bitcoin-cli getblockhash 935000
10000000000000000000147034958af1652b2b91bba607beacc5e72a56f0fb5ee
2
3$ bitcoin-cli getblockhash 938343
400000000000000000000ccebd6d74d9194d8dcdc1d177c478e094bfad51ba5ac

 0# tip: 935'000
 1$ bitcoin-cli gettxoutsetinfo hash_serialized_3
 2{
 3  "height": 935000,
 4  "bestblock": "0000000000000000000147034958af1652b2b91bba607beacc5e72a56f0fb5ee",
 5  "txouts": 164241311,
 6  "bogosize": 12870854130,
 7  "hash_serialized_3": "e4b90ef9eae834f56c4b64d2d50143cee10ad87994c614d7d04125e2a6025050",
 8  "total_amount": 19984148.03206779,
 9  "transactions": 113879165,
10  "disk_size": 13290295029
11}

 0# tip: 935'000
 1$ bitcoin-cli getchaintxstats 4096
 2{
 3  "time": 1770215102,
 4  "txcount": 1305397408,
 5  "window_final_block_hash": "0000000000000000000147034958af1652b2b91bba607beacc5e72a56f0fb5ee",
 6  "window_final_block_height": 935000,
 7  "window_block_count": 4096,
 8  "window_interval": 2660438,
 9  "window_tx_count": 11723636,
10  "txrate": 4.406656347563822
11}

 0# tip: 938'343
 1$ bitcoin-cli getchaintxstats 4096
 2{
 3  "time": 1772055173,
 4  "txcount": 1315805869,
 5  "window_final_block_hash": "00000000000000000000ccebd6d74d9194d8dcdc1d177c478e094bfad51ba5ac",
 6  "window_final_block_height": 938343,
 7  "window_block_count": 4096,
 8  "window_interval": 2346169,
 9  "window_tx_count": 12671917,
10  "txrate": 5.40111006496122
11}

 0$ bitcoin-cli getblockheader 00000000000000000000ccebd6d74d9194d8dcdc1d177c478e094bfad51ba5ac
 1{
 2  "hash": "00000000000000000000ccebd6d74d9194d8dcdc1d177c478e094bfad51ba5ac",
 3  "confirmations": 1,
 4  "height": 938343,
 5  "version": 671891456,
 6  "versionHex": "280c4000",
 7  "merkleroot": "1bd0deca15c01a0b62b9f56b5310004d41678c8be829b2ec5fc93ff3a8041c00",
 8  "time": 1772055173,
 9  "mediantime": 1772052403,
10  "nonce": 3140788553,
11  "bits": "1701f303",
12  "target": "00000000000000000001f3030000000000000000000000000000000000000000",
13  "difficulty": 144398401518100.9,
14  "chainwork": "0000000000000000000000000000000000000001128750f82f4c366153a3a030",
15  "nTx": 3963,
16  "previousblockhash": "00000000000000000000bf88bc08552c46937df889b9e0cfe1141da456923b3c"
17}

testnet4

m_assumeutxo_data @ 120'000
chainTxData @ 120'000
consensus.nMinimumChainWork @ 123'613
consensus.defaultAssumeValid @ 123'613

0magnet:?xt=urn:btih:25733a7e451ca435f2901921b805c167f560424d&dn=utxo-testnet4-120000.dat&tr=udp%3A%2F%2Ftracker.bitcoin.sprovoost.nl%3A6969&tr=udp%3A%2F%2Ftracker.opentrackr.org%3A1337%2Fannounce

sha256: 093b44c537d207d7daf3367b00e7c71323d0163b7ae3d73f76ea05479a945f9c

0$ bitcoin-cli getblockhash 120000
1000000000bd2317e51b3c5794981c35ba894ce27d3e772d5c39ecd9cbce01dc8
2
3$ bitcoin-cli getblockhash 123613
40000000002368b1e4ee27e2e85676ae6f9f9e69579b29093e9a82c170bf7cf8a

 0# tip: 120'000
 1$ bitcoin-cli gettxoutsetinfo hash_serialized_3
 2{
 3  "height": 120000,
 4  "bestblock": "000000000bd2317e51b3c5794981c35ba894ce27d3e772d5c39ecd9cbce01dc8",
 5  "txouts": 13870119,
 6  "bogosize": 1142705000,
 7  "hash_serialized_3": "10b05d05ad468d0971162e1b222a4aa66caca89da2bb2a93f8f37fb29c4794b0",
 8  "total_amount": 5999799.97251533,
 9  "transactions": 9181935,
10  "disk_size": 1023009172
11}

 0# tip: 120'000
 1$ bitcoin-cli getchaintxstats 4096
 2{
 3  "time": 1769234583,
 4  "txcount": 14141057,
 5  "window_final_block_hash": "000000000bd2317e51b3c5794981c35ba894ce27d3e772d5c39ecd9cbce01dc8",
 6  "window_final_block_height": 120000,
 7  "window_block_count": 4096,
 8  "window_interval": 2168096,
 9  "window_tx_count": 56313,
10  "txrate": 0.02597348087907547
11}

 0# tip: 123'613
 1$ bitcoin-cli getchaintxstats 4096
 2{
 3  "time": 1772013387,
 4  "txcount": 14191421,
 5  "window_final_block_hash": "0000000002368b1e4ee27e2e85676ae6f9f9e69579b29093e9a82c170bf7cf8a",
 6  "window_final_block_height": 123613,
 7  "window_block_count": 4096,
 8  "window_interval": 2993163,
 9  "window_tx_count": 55331,
10  "txrate": 0.01848579579528412
11}

 0$ bitcoin-cli getblockheader 0000000002368b1e4ee27e2e85676ae6f9f9e69579b29093e9a82c170bf7cf8a
 1{
 2  "hash": "0000000002368b1e4ee27e2e85676ae6f9f9e69579b29093e9a82c170bf7cf8a",
 3  "confirmations": 9,
 4  "height": 123613,
 5  "version": 1073733632,
 6  "versionHex": "3fffe000",
 7  "merkleroot": "0e9f83f33fc7913d7c088411675c5fc8f22fc9f796d6afde7a1b1938da4242e6",
 8  "time": 1772013387,
 9  "mediantime": 1772007382,
10  "nonce": 2783855826,
11  "bits": "1d00ffff",
12  "target": "00000000ffff0000000000000000000000000000000000000000000000000000",
13  "difficulty": 1,
14  "chainwork": "0000000000000000000000000000000000000000000009a0fe15d0177d086304",
15  "nTx": 1,
16  "previousblockhash": "0000000009feb85d0c1076552f914835055a86032fdbcce1c821b5a624acfa00",
17  "nextblockhash": "0000000007f977533c5fa7d5de287be9d3b30f63dfbf4e17648f6e5d0a4e907c"
18}

testnet3

m_assumeutxo_data @ 4'840'000
chainTxData @ 4'840'000
consensus.nMinimumChainWork @ 4'842'348
consensus.defaultAssumeValid @ 4'842'348

0magnet:?xt=urn:btih:dfe62321ec8e9538a47e4f019d34a88510eaa751&dn=utxo-testnet-4840000.dat&tr=udp%3A%2F%2Ftracker.bitcoin.sprovoost.nl%3A6969&tr=udp%3A%2F%2Ftracker.opentrackr.org%3A1337%2Fannounce

sha256: eacaf9f1cdf6ddcc182ca255ffa3c423b592aede0abdbb4504079df586a22981

0$ bitcoin-cli getblockhash 4840000
100000000000000f4971a7fb37fbdff89315b69a2e1920c467654a382f0d64786
2
3$ bitcoin-cli getblockhash 4842348
4000000007a61e4230b28ac5cb6b5e5a0130de37ac1faf2f8987d2fa6505b67f4

 0# tip: 4'840'000
 1$ bitcoin-cli gettxoutsetinfo hash_serialized_3
 2{
 3  "height": 4840000,
 4  "bestblock": "00000000000000f4971a7fb37fbdff89315b69a2e1920c467654a382f0d64786",
 5  "txouts": 235037810,
 6  "bogosize": 18882533444,
 7  "hash_serialized_3": "ce6bb677bb2ee9789c4a1c9d73e6683c53fc20e8fdbedbdaaf468982a0c8db2a",
 8  "total_amount": 20999097.89823624,
 9  "transactions": 151886949,
10  "disk_size": 16634570050
11}

 0# tip: 4'840'000
 1$ bitcoin-cli getchaintxstats 4096
 2{
 3  "time": 1770358647,
 4  "txcount": 536078574,
 5  "window_final_block_hash": "00000000000000f4971a7fb37fbdff89315b69a2e1920c467654a382f0d64786",
 6  "window_final_block_height": 4840000,
 7  "window_block_count": 4096,
 8  "window_interval": 1276608,
 9  "window_tx_count": 62368,
10  "txrate": 0.04885446433047576
11}

 0# tip: 4'842'348
 1$ bitcoin-cli getchaintxstats 4096
 2{
 3  "time": 1772051651,
 4  "txcount": 536108416,
 5  "window_final_block_hash": "000000007a61e4230b28ac5cb6b5e5a0130de37ac1faf2f8987d2fa6505b67f4",
 6  "window_final_block_height": 4842348,
 7  "window_block_count": 4096,
 8  "window_interval": 2328088,
 9  "window_tx_count": 62660,
10  "txrate": 0.02691479016257117
11}

 0$ bitcoin-cli getblockheader 000000007a61e4230b28ac5cb6b5e5a0130de37ac1faf2f8987d2fa6505b67f4
 1{
 2  "hash": "000000007a61e4230b28ac5cb6b5e5a0130de37ac1faf2f8987d2fa6505b67f4",
 3  "confirmations": 1,
 4  "height": 4842348,
 5  "version": 536870912,
 6  "versionHex": "20000000",
 7  "merkleroot": "6c3083cb05ca4798dd4fb9343cf544a20e8172035b8645ad946195c4e0e91a68",
 8  "time": 1772051651,
 9  "mediantime": 1772045594,
10  "nonce": 1509827168,
11  "bits": "1d00ffff",
12  "target": "00000000ffff0000000000000000000000000000000000000000000000000000",
13  "difficulty": 1,
14  "chainwork": "0000000000000000000000000000000000000000000017dde1c649f3708d14b6",
15  "nTx": 17,
16  "previousblockhash": "0000000032167e59d45f0861dc426ec95b6d5850e69121bde56ae6eb25eebd8a"
17}

signet

m_assumeutxo_data @ 290'000
chainTxData @ 290'000
consensus.nMinimumChainWork @ 293'175
consensus.defaultAssumeValid @ 29'3175

0magnet:?xt=urn:btih:304c3ee0ac2ce34ba64173b50d1950976544e8a3&dn=utxo-signet-290000.dat&tr=udp%3A%2F%2Ftracker.bitcoin.sprovoost.nl%3A6969&tr=udp%3A%2F%2Ftracker.opentrackr.org%3A1337%2Fannounce

sha256: 12d1b3f1e3488ddea251b8222e4ecf8552de2aa73c9fe05f94a08a1eb5eba367

0$ bitcoin-cli getblockhash 290000
10000000577f2741bb30cd9d39d6d71b023afbeb9764f6260786a97969d5c9ac0
2
3$ bitcoin-cli getblockhash 293175
400000008414aab61092ef93f1aacc54cf9e9f16af29ddad493b908a01ff5c329

 0# tip: 290'000
 1$ bitcoin-cli gettxoutsetinfo hash_serialized_3
 2{
 3  "height": 290000,
 4  "bestblock": "0000000577f2741bb30cd9d39d6d71b023afbeb9764f6260786a97969d5c9ac0",
 5  "txouts": 59319793,
 6  "bogosize": 4753561406,
 7  "hash_serialized_3": "97267e000b4b876800167e71b9123f1529d13b14308abec2888bbd2160d14545",
 8  "total_amount": 12499727.17741007,
 9  "transactions": 11145919,
10  "disk_size": 3498668523
11}

 0# tip: 290'000
 1$ bitcoin-cli getchaintxstats 4096
 2{
 3  "time": 1770163902,
 4  "txcount": 28547497,
 5  "window_final_block_hash": "0000000577f2741bb30cd9d39d6d71b023afbeb9764f6260786a97969d5c9ac0",
 6  "window_final_block_height": 290000,
 7  "window_block_count": 4096,
 8  "window_interval": 2459211,
 9  "window_tx_count": 158216,
10  "txrate": 0.06433608177582159
11}

 0# tip: 293'175
 1$ bitcoin-cli getchaintxstats 4096
 2{
 3  "time": 1772055248,
 4  "txcount": 28676833,
 5  "window_final_block_hash": "00000008414aab61092ef93f1aacc54cf9e9f16af29ddad493b908a01ff5c329",
 6  "window_final_block_height": 293175,
 7  "window_block_count": 4096,
 8  "window_interval": 2435790,
 9  "window_tx_count": 164090,
10  "txrate": 0.06736623436338929
11}

 0$ bitcoin-cli getblockheader 0000000002368b1e4ee27e2e85676ae6f9f9e69579b29093e9a82c170bf7cf8a
 1{
 2  "hash": "00000008414aab61092ef93f1aacc54cf9e9f16af29ddad493b908a01ff5c329",
 3  "confirmations": 1,
 4  "height": 293175,
 5  "version": 536870912,
 6  "versionHex": "20000000",
 7  "merkleroot": "664431bfbd5f0d84be6a71b5f19f936d6ecb6e3cfbbe315212b6eedc927408c6",
 8  "time": 1772055248,
 9  "mediantime": 1772050304,
10  "nonce": 36906233,
11  "bits": "1d150eea",
12  "target": "000000150eea0000000000000000000000000000000000000000000000000000",
13  "difficulty": 0.0474865840527392,
14  "chainwork": "00000000000000000000000000000000000000000000000000000b463ea0a4b8",
15  "nTx": 109,
16  "previousblockhash": "0000000e14aa494dc78672c43bf4095b3360a597ded2fcb985ccd67aa76b0d7e"
17}

Sjors commented at 5:58 pm on March 3, 2026: member

ACK 44538f8ada868cb73ffa7a4bfb5267046d3f6b85

 0-----BEGIN PGP SIGNED MESSAGE-----
 1Hash: SHA256
 2
 3ACK 44538f8ada868cb73ffa7a4bfb5267046d3f6b85
 4
 5I didn't do a full resync though.
 6-----BEGIN PGP SIGNATURE-----
 7
 8iQIzBAEBCAAdFiEE7ZvfetalXiMuhFJCV/+b28wwEAkFAmmnITcACgkQV/+b28ww
 9EAkQrg/+LtAPghtieJQJNpY8ZVqNRbavdfDuXWR2WT15l6nIXBWHscHutJKYgalR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20=WzpI
21-----END PGP SIGNATURE-----

DrahtBot requested review from jaonoctus on Mar 3, 2026

sipa commented at 2:58 pm on March 5, 2026: member

ACK 44538f8ada868cb73ffa7a4bfb5267046d3f6b85. I re-did all the mainnet parameters, but did not look closely at the other networks.

jaonoctus commented at 9:12 pm on March 5, 2026: none

ACK 44538f8ada868cb73ffa7a4bfb5267046d3f6b85

#34677#pullrequestreview-3869225696

fjahr commented at 11:53 pm on March 6, 2026: contributor

ACK 44538f8ada868cb73ffa7a4bfb5267046d3f6b85

I have re-done the mainnet, testnet4 and signet params.

fanquake merged this on Mar 8, 2026

fanquake closed this on Mar 8, 2026

kernel: Chainparams and headerssync updates pre-31.0 #34677

Reviews

Conflicts

LLM Linter (✨ experimental)

mainnet

testnet4

testnet3

signet