diff --git a/CONTEXT.md b/CONTEXT.md
index 49609c0..a85fa39 100644
--- a/CONTEXT.md
+++ b/CONTEXT.md
@@ -7,7 +7,17 @@
 >
 > Ask Claude Code: "Please update CONTEXT.md with what we did today"
 
-Last updated: 2026-09-25 night (v0.271.0 — automatic app updates, `09` §6.4 part 7; R-680, R-678; floor 0.271.0)
+Last updated: 2026-09-27 (v0.275.0 — a backup's data and its version travel together; floor 0.275.0)
+
+> **2026-09-27 — v0.275.0, floor 0.275.0 (MinAgent 0.131.0).** `backup/data_versions.go`: `stampDataFile` (called by the
+> DB leg, the volume leg and `RunAppBackupNow` — a new writer of a unit data file MUST call it), `foldUnitData`,
+> `RecoveryManifest.Data`; `captureRecoveryUnit(stack, dataRun)` keeps `compose/` when the pins moved since the data
+> (frozen); `unitVersionCheck`/`ErrUnitVersionMismatch` in the unit restore and the off-site reconstitute (which now
+> writes the snapshot's definition when versions differ); `unitDataTime` = THE unit data time (+ proven flag, R-699);
+> Tier 2 `DataDate`/`DataUnproven`; Tier 3 `offsiteDataTime`; `stacks.DumpStampSource` (optional guards interface) +
+> `ConversionCopy.Service`; `stacks.RestoredVersionPosition` + the restore pages' first sentence; R-695 single-flight
+> FB sync; R-691 `keptReadGroups`/`group_add` (CC-unattended decision, `07` §6.5); R-694 `restored_logins`.
+> D4 (open) option A is the built behaviour — `07` §6.6.
 
 > **2026-09-25 midday — v0.272.0, floor 0.272.0.** `web.noSpaceLine` (agent prefix `skipped: not enough space: `,
 > key `backup.tier.no_space`); `backup.SetUndoCopyRemover` → `stacks.RemoveUndoCopies` from `clearUpdateHoldAfterRestore`
diff --git a/REPORT.md b/REPORT.md
index af39130..f63a647 100644
--- a/REPORT.md
+++ b/REPORT.md
@@ -1,31 +1,26 @@
-# REPORT — controller v0.273.0 + v0.274.0 (2026-09-25)
+# REPORT — v0.275.0: a backup's data and its version travel together (2026-09-26/27)
 
-Two releases in one session, as the brief allowed: **v0.273.0** (`5a731b4`) — the PostgreSQL major conversion
-(`09` §3 decisions 35, 37, 38; §6.4 part 10) + R-687's two small items; **v0.274.0** (`64cbefe`) — kept data (decision
-36) + R-690 + R-692. Floor 0.273.0 then 0.274.0, MinAgent 0.131.0 declared both times, read back from the hub; both
-demo boxes arrived healthy within ~25 s each time. CI: `5a731b4` job 1002 success.
+Brief: version-travel (Parts A, D2–D4). Architecture: `07-backup-architecture.md` §6 (+ new §6.6), `09` §3, §5.3, §6.4.
+Session record: `felhom.eu/documentation/audits/DRILL-version-travel-2026-09-26.md`.
 
-**The conversion** (`internal/stacks/pgconvert.go`): only on a ladder step marked `engine_conversion`; a PostgreSQL
-major move without the mark is refused by the preflight and the job. Phase `converting` after the undo copy: old
-engine alone → check (owners, encodings, roles, extensions, per-table row counts) → `pg_dumpall` with its completion
-line → the volume emptied only after the copy's marker is validated again → new engine alone → entrypoint databases
-dropped, existing roles' `CREATE ROLE` skipped → load with `ON_ERROR_STOP` → check equal + `PG_VERSION`. Any failure,
-and a restart during `converting`, runs the existing undo. The old datadir's copy stays until a backup is proven
-after the conversion (hourly `conversion-copy-release`). **Live on 9202** (`0.273.0-rc1`, drill catalog): docmost
-16 → 18 done in 42 s (9.9 s of engine work, 48 tables / 71 rows equal); the load failing (`adminpack`, gone in 17+) →
-undone in 43.6 s; the app unhealthy on 18 → undone in 148 s; SIGKILL one second after the volume was emptied → the
-restart undid it in 40 s; each ending on 16 with the seed read back. Found live and fixed: the recovery line said
-UNDOING for a restart during `converting`. **Red-proofs:** 9 (conversion) + 2 (R-687) + 1 (R-692) here; the Part E
-build carries 10 more (`felhom.eu/documentation/audits/night-2026-09-26/E/redproofs/`).
+**Baseline:** `main` `fb2bcdd5d619`, v0.274.0, floor 0.274.0. **Commits:** `b6810f1` (Part A, R-695, R-691 (1), R-694),
+`7fcda8f` (R-699, found live). **Released:** image `0.275.0` (rc `0.275.0-rc1` for the live proofs); floor 0.275.0 with
+MinAgent 0.131.0 — both demo boxes on 0.275.0 within 15 s (`audits/version-travel-2026-09-26/R/`); 9202 by hand (scratch).
 
-**Kept data** (`internal/stacks/kept.go`, `internal/web/kept_handlers.go`, `internal/api/kept_install.go`): built by a
-parallel helper session in its own worktree, reviewed and proven here. The install over a non-empty drive folder answers
-409 `kept_data_choice` until „use my kept data" / „start fresh" is chosen; the „Megőrzött adatok" / "Kept data" page
-lists, loads, deletes (typed); a read-only file-browser source; `<drive>/kept` protected and never backed up; the
-drive-full warning names kept folders. **R-692 found live** (the list named leftovers „Filebrowser") and fixed before
-the release. **Live on 9202** (endpoint level, both languages): the whole E5 walk passed — see
-`felhom.eu/documentation/audits/night-2026-09-26/E/E5-*`.
+**Tests:** full suite green (`go build/vet/test ./...` rc=0) after the last change; controller gates all OK. New tests:
+`internal/backup/a_version_travel_test.go` (15), `internal/stacks` `TestA5_TheReleaseRefusesAPreConversionDump`,
+`TestA4_AnOldRecordWithoutAServiceChecksEveryPostgresImage`, `TestA3_RestoredVersionPosition`, `TestR695_*`, `TestR694_*`,
+`internal/web` `TestA3_RestoredVersionSentence`, `TestR695_*`, `TestR691_*` (2), `TestR694_*`; new parity fixture
+`deploy_deployed_restored_login`. Two AST fixture names updated (`TestAdmission_IsWiredIntoEveryProductionWriteLeg`).
 
-**Not done:** R-691 (a 0770 folder is not readable in the view; "use" does not look off-site); R-694 (what the page
-shows after a load regenerates a withheld login secret) — measure first. Full session record:
-`felhom.eu/documentation/audits/DRILL-night-2026-09-26.md`.
+**Red-proofs (each seen failing, tree restored)** — `felhom.eu/documentation/audits/version-travel-2026-09-26/`:
+RP1 Tier 1 time = manifest ("the refresh 1s made a two-hour-old dump read as new"); RP2/RP2b the refresh rewrites
+`compose/` (the restore started 16 data with `postgres:18`); RP3 no version check (mismatch/mixed restored); RP4 the
+release on a pre-conversion dump ("released [nextcloud]; copies=0"); RP5 off-site uses the live definition; RP6 R-699 (a
+dump-less unit accepted); D2 R-695 ×2; D3 R-691 ×2; D4 R-694.
+
+**Live (endpoint level, 9202):** `A5-live/README.md` — both shapes restore the old version whole and climb again; the box's
+own night showed the frozen definition and the data-time restore point.
+
+**NOT yet live-validated:** the off-site restore's definition write; the conversion-copy release on a real 18 dump (due
+after 9202's next nightly backup); R-691 (1) with a real 0770 folder; the English restore sentence.