[juaristi22]

Summary

The UK lock moves from policyengine-uk 2.174.1 to 2.177.7, the newest release when the pin moved (microcosm#1095). From 2.177.4 policyengine-uk requires policyengine-core 3.34.9 or later, so the UK side's core moves from 3.33.3 to 3.34.10, the newest. The US side stays on 3.32.5, and uv.lock moves those two packages alone. What each release since the lock needs is in #1095's "The next policyengine-uk lock" (the read of 10 November), and the releases after it, 2.177.5 to 2.177.7, are below.

This PR was opened stacked on #1550. #1550 merged on 10 November (bd09f1783), and main at that commit is merged into this branch. After that merge the pin moved from 2.177.4 to 2.177.7, as María chose. 2.177.5 to 2.177.7 add no input.

The three new inputs, signed at their defaults

Each is in UK_ENGINE_DEFAULT_INPUTS with the error it can make, for María's signature:

• legacy_prescribed_accommodation_capital_exception (2.174.8), at False: the FRS samples private households, so it holds almost no claimant living permanently in prescribed accommodation. Such a claimant's Income Support, income-based JSA or income-related ESA is understated by the tariff income on capital between £6,000 and £10,000.
• esa_income_appointee_saving (2.175.3), at False: the FRS does not identify appointees, so every reported income-related ESA award ends at the abolition of 1 July 2026. DWP exempted around 500 such claimants. 2025, the calibration year, does not move.
• cares_for_severely_disabled_person (2.177.3), at True: the FRS records caring hours but not whom the carer cares for. At True, caring hours pay as before, so no figure moves.

An input that gained a formula

From 2.176.1, is_before_universal_credit_qualifying_young_person_terminal_date follows the date of birth, so it leaves the engine's input surface (376 to 378 inputs). frs_education still writes it, and the loader takes a stored value over the formula, as it does for any engine variable. Universal Credit reads it only for a 19-year-old, together with the education condition, which is the same test frs_education sets it from. So the stored value and the formula give the same result.

What the build's engine reads return now

• 2.174.2 to 2.175.3: as UK: every open data item: uk-data parity, engine locks, the local surface, consumption and high-value homes #1095 lists them. The qualifying young person rule for 16-year-olds; the State Pension age addition; the benefit cap reduction; the Universal Credit deduction flag; reg 60A's Working Tax Credit test; Maternity Allowance in the cap; and the income-related ESA abolition, which moves nothing before July 2026.

• 2.175.5, 2.175.8 and 2.177.2 (Council Tax Reduction):

  • the pensioner schemes in England, Scotland and Wales add child amounts and family premiums;
  • all of a Scottish pensioner's capital over £10,000 counts in tariff income;
  • Scotland's and Wales's working-age schemes get their own rules;
  • Scotland's counts Carer Support Payment after the overlapping-benefit reduction.

  The council tax rows read council tax net of the reduction.

• 2.176.0 (Model rent from boarders, lodgers and sub-tenants for the householder policyengine-uk#2002): rent from boarders, lodgers and sub-tenants for the householder.

  • Income tax gives rent-a-room relief on the boarders' and lodgers' rent, which the engine sums for the household head from the rent_paid_as_boarder and rent_paid_as_lodger the build writes.
  • The legacy means tests apply the £20 and board-and-lodging disregards.
  • A boarder or lodger draws no non-dependant deduction.
  • The build keeps the FRS sub-letting rent in property_income.

• 2.176.1: the qualifying young person's terminal date, above. It now applies to Pension Credit too.

• 2.176.2:

  • Housing Benefit's and national Council Tax Reduction's non-dependant deductions follow each scheme's rules.
  • Universal Credit changes its LHA bedrooms and its renter exemption.
  • Universal Credit's benefit cap counts welfare benefits without Housing Benefit. A dataset that supplied benefit_cap_welfare_benefits would now also need Housing Benefit before the cap; the build supplies neither.

• 2.177.0: VAT's survey coverage moves from 0.67 to 0.69. obr.vat stays held.

• 2.177.2: Marriage Allowance becomes the recipient's tax reduction, and Scottish taxpayers' tax bands apply the Scottish limits to income other than savings and dividends.

• 2.177.3: Plan 5 borrowers repay nothing before 6 April 2026, the date the student-loans stage already uses. slc.borrowers.plan_5_above_threshold then matches SLC's nil, and slc.repayments.england_plan_5, held, reads nil.

• 2.177.5 (Bar income-related ESA at pensionable age and on Pension Credit policyengine-uk#2807): no income-related ESA for a claimant who has reached pensionable age, or for a couple that would get Pension Credit without it.

• 2.177.6 (Count enhanced PIP daily living and AFIP for the enhanced premium policyengine-uk#2808):

  • The legacy enhanced disability premium is paid for enhanced PIP daily living and armed forces independence payment, beside the highest DLA care rate.
  • Four councils' working-age CTR schemes get their own lists.
  • The is_enhanced_disabled_for_benefits the build stores now reaches only Kingston upon Thames's working-age Council Tax Reduction and two deprecated counts, neither of which the build reads.
  • No stage writes armed forces independence payment, so its recipients get the premium only through another qualifying benefit.

• 2.177.7 (Set reliefs and allowances against income for the least tax policyengine-uk#2830): income tax sets the allowances and reliefs against income in the way that gives the least tax (ITA 2007 s. 25(2)), instead of against non-savings income first.

• policyengine-core 3.34.10: fixes to cached periods and to inputs on reform branches. The UK side neutralises no variable and uses none of the APIs 3.34.0 removed.

• The other releases change nothing the build reads at 2024 or 2025, or nothing at all.

What does not move

• The vendored uprating pins and the bonus-sacrifice anchor change only their version stamps. The CGT projection path keeps its values, within the pinned drift (test_uk_cgt_projection.py).
• UK_HBAI_GROSS_INCOME_DEDUCTIONS keeps its parity. 2.176.0 adds sublet_income to HBAI income, not to its subtractions, and the build keeps that income in property_income.

Texts and derived files

Every text that described the locked engine was checked against the diff from 2.174.1 to 2.177.7 and now cites 2.177.7. That covers the stage notes, code comments, test docstrings, the ISA and LISA docs, and #1550's PIP points, limited capability and trading allowance texts. Among the variables they cite, 2.177.5 to 2.177.7 change only tax_band's comment.

The take-up stage's note had said the build flags nobody in full-time education. Since #1535 it does, and the note now says so, as the code comment does. The coverage manifest tool's PIP notes and the eFRS known gaps follow.

The concept coverage report, the release input coverage manifest, the H2 fixture, the cited versions and APPROVED_UV_LOCK_SHA256 are regenerated.

Measurement

Two arms run on this machine, one at a time, each a spine and a calibration, at review date 2026-11-10 on #1550's feed (8045b138):

• a control on main at bd09f1783, this PR's base;
• this branch's head at 9e58d5844, which is also certified as a national release: rule 1 against the enhanced FRS, the signed release-cut certification, and the stage-1 comparison with the promoted national. Published to the inspect lane by tag, without promotion, it can be loaded by that tag for data drills on a certified dataset.

Rule 1 on the head build refused at first. Five HMRC SPI rows have read person.trading_allowance_full_relief since #1439, and the measure had no entry on the reviewed incumbent-unresolvable register. Main has the same gap. aa08d812b adds María's signed entry and changes nothing the build reads, so the certification reruns on the same build at that commit.

The control is fresh because main's merges since #1550 branched change the national build: #1549's register, #1417's ITL differential check and the fiscal targets. Their results follow in a comment: both arms' gates, the fit, the first stage where the spines differ, and the rows each release moves, with rows of the SPI channel as classes.

Tests

• Engine tier on policyengine-uk 2.177.7: CI's engine-uk job at 9e58d5844 (72 files on Python 3.13 and 3.14), which includes the H parity test, passed on both, as did every other job of that run.
• Engine tier on 2.177.4: CI's engine-uk list (72 files), run in full locally because CI stops at the first failure. 315 tests: 313 passed and 2 failed, and 5d6a3e7 fixes both.
  • test_uk_tax_band_measure.py had pinned a known gap "so a fix shows", and 2.177.2 is that fix.
  • The frozen eFRS candidate receipt measures the terminal-date column against its engine default, which 2.176.1 flips; the receipt keeps its original engine provenance.
  • The checklist tests passed: the CGT projection, bus parity, UK_HBAI_GROSS_INCOME_DEDUCTIONS, the uprating pins, the bonus anchor and all 13 concept-mapping tests.
• Engine-free files on the touched surfaces: 81 files, run in three processes and counted by --junitxml. 3,904 tests: 3,877 passed, 25 skipped and 2 failed, neither from this PR.
  • The first was UK November event data, PR2: feed re-pin, trading allowance claim status, Scottish council tax and NSND, young people and PIP rows, UC take-up age fit, PIP points, UC limited capability #1550's own stale stage-order pin, which 8780aa3 fixes.
  • The second was test_us_release_head_to_head_scorer, whose guard refuses this machine's Python 3.14.6. CI's engine-free (3.14) job at aa08d812b hit the same refusal on an ubuntu-26.04 runner's Python 3.14.4. Since 8fc423fc0 that test runs without recycling on such interpreters, and its 18 tests pass here. The same runner's uv wrapped a conflict error inside the phrase test_uv_refuses_every_us_and_uk_combination looks for; since 86bad5008 it reads the error with its whitespace collapsed.
  • On 2.177.7 the core pins, the manifest and the source-stage files pass (68 tests).
• Checks on 2.177.7:
  • tools/ci_test_plan.py verify;
  • tools/spec_engine_coverage.py --check (42,394 of 42,394 fields, 41 of 41 inventory checks);
  • tools/refresh_concept_coverage.py --engine policyengine-uk --check;
  • the coverage manifest with --check;
  • the H2 fixture, regenerated on 2.177.7 in 9e58d5844. Only the engine versions and four stage contract digests move, and no fixture value.
• The register entry (aa08d812b): the six engine-free files that read the register pass (228 tests).

Signatures

Awaiting María's signature: the three signed defaults, with the error each can make.

Signed by María on 10 November: the incumbent-unresolvable entry for person.trading_allowance_full_relief (aa08d812b), expiring 10 February 2027.

Not in this PR

• The SUBRENT move to sublet_income, which 2.176.0 now allows (Move SUBRENT from property_income to sublet_income, after policyengine-uk reads sublet_income policyengine-uk-data#508's order).
• The obr.vat rebind, whose condition in María's ruling of 24 October 2.177.0 meets.
• The restated reason for the Plan 5 repayments row.
• Give household situations no share of national totals, and let data carry UK totals policyengine-uk#2901, in pe-uk's merge queue. It adds 14 uk_total_* household inputs, which the build would sign at 0 or write with add_uk_totals: a follow-up.

Disclosure

No figure in this PR, its commits or its changelog rests on survey records. The numbers are policyengine-uk's parameters and versions, and published figures cited as their publishers'.

🤖 Generated with Claude Code