diff --git a/module.json b/module.json
index 26610c2..d859dbb 100644
--- a/module.json
+++ b/module.json
@@ -1,7 +1,7 @@
 {
   "id": "uo",
   "name": "Ultima Online",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "coreApi": "^1.3.0",
   "server": "server/index.js",
   "client": { "entry": "client/dist/entry.js" },
diff --git a/server/db/schema.sql b/server/db/schema.sql
index b370e20..e86ca58 100644
--- a/server/db/schema.sql
+++ b/server/db/schema.sql
@@ -47,7 +47,7 @@ CREATE TABLE IF NOT EXISTS uo_link_config (
   base_url          VARCHAR(255) NULL,
   ws_url            VARCHAR(255) NULL,
   auth_token_enc    TEXT         NULL,
-  protocol          INT          NOT NULL DEFAULT 4,
+  protocol          INT          NOT NULL DEFAULT 5,
   enabled           TINYINT(1)   NOT NULL DEFAULT 0,
   status            VARCHAR(20)  NOT NULL DEFAULT 'disconnected',
   status_detail     VARCHAR(500) NULL,
@@ -727,3 +727,62 @@ ALTER TABLE shard_guild_members ADD COLUMN IF NOT EXISTS `rank` TINYINT NULL;
 ALTER TABLE shard_guild_members ADD COLUMN IF NOT EXISTS rank_cliloc INT NULL;
 ALTER TABLE shard_guild_members ADD COLUMN IF NOT EXISTS rank_name VARCHAR(64) NULL;
 ALTER TABLE shard_guild_members ADD INDEX IF NOT EXISTS idx_shard_guild_members_rank (guild_id, `rank`);
+
+-- ── Protocol 5 ───────────────────────────────────────────────────────────────
+--
+-- Three wire enrichments, bumped together (link/sidecar/src/main.rs, overlay.toml).
+-- Two of them land as columns here; the third is a new event kind and needs none.
+--
+-- 1. house.decay's decay SCHEDULE. `shard_houses` could say what stage a house was
+--    at and when it was last refreshed, but nothing about WHEN the next thing
+--    happens — which is the only part a player can act on. `estimated_collapse` is
+--    nullable and stays null far more often than not, deliberately: under dynamic
+--    decay (Core.ML) ServUO draws each stage's duration at random when the stage is
+--    entered, so collapse is exactly knowable only once the house is already at
+--    IDOC. A null here means "not knowable", never "not yet read".
+ALTER TABLE shard_houses ADD COLUMN IF NOT EXISTS next_stage DATETIME NULL;
+ALTER TABLE shard_houses ADD COLUMN IF NOT EXISTS estimated_collapse DATETIME NULL;
+ALTER TABLE shard_houses ADD COLUMN IF NOT EXISTS decay_period_sec INT NULL;
+ALTER TABLE shard_houses ADD COLUMN IF NOT EXISTS dynamic_decay TINYINT(1) NULL;
+
+-- 2. vendor.listing's owner account and fee state.
+--
+--    `owner_acct` is the one that matters structurally: the table has carried
+--    `owner_name` since Protocol 3, but a character name is not an identity — only
+--    the game ACCOUNT joins to shard_account_links, so until now a vendor row named
+--    an owner the site could not resolve to a user.
+--
+--    The fee columns describe PlayerVendor.PayTimer's dismissal rule: at each tick
+--    the charge is compared with the funds and the vendor is destroyed when the
+--    charge wins. `dismissal_at` is that comparison resolved into an instant, which
+--    is what any surface actually wants; the parts are kept alongside it so a
+--    display can explain the number rather than only state it.
+--
+--    `fees_exempt` marks a commission vendor: it has no pay timer at all and is
+--    never dismissed for fees, which is a different thing from having a long time
+--    left and must not render as one.
+ALTER TABLE shard_vendors ADD COLUMN IF NOT EXISTS owner_acct VARCHAR(120) NULL;
+ALTER TABLE shard_vendors ADD COLUMN IF NOT EXISTS fees_exempt TINYINT(1) NOT NULL DEFAULT 0;
+ALTER TABLE shard_vendors ADD COLUMN IF NOT EXISTS charge_per_period INT NULL;
+ALTER TABLE shard_vendors ADD COLUMN IF NOT EXISTS funds INT NULL;
+ALTER TABLE shard_vendors ADD COLUMN IF NOT EXISTS pay_interval_sec INT NULL;
+ALTER TABLE shard_vendors ADD COLUMN IF NOT EXISTS next_pay_at DATETIME NULL;
+ALTER TABLE shard_vendors ADD COLUMN IF NOT EXISTS periods_remaining INT NULL;
+ALTER TABLE shard_vendors ADD COLUMN IF NOT EXISTS dismissal_at DATETIME NULL;
+-- Both of these exist for the same reader: the Phase 11 trigger that has to find
+-- "vendors about to be dismissed" without scanning every shop, and the owner join
+-- that turns one into a person.
+ALTER TABLE shard_vendors ADD INDEX IF NOT EXISTS idx_shard_vendors_dismissal (dismissal_at);
+ALTER TABLE shard_vendors ADD INDEX IF NOT EXISTS idx_shard_vendors_owner_acct (owner_acct);
+
+-- 3. The protocol pin, one step on from the Protocol 4 block above and for exactly
+--    the reasons it spells out. `protocol < 5` rather than `= 4`, so an install that
+--    missed an earlier migration is carried the whole way; the one-shot marker is
+--    written here in the module's own fragment, because core's schema is replayed in
+--    full BEFORE any module fragment and a marker left in core would already exist
+--    when this UPDATE read it.
+ALTER TABLE uo_link_config MODIFY COLUMN protocol INT NOT NULL DEFAULT 5;
+UPDATE uo_link_config SET protocol = 5
+  WHERE id = 1 AND protocol < 5
+    AND NOT EXISTS (SELECT 1 FROM settings WHERE `key` = 'uo_link_protocol_5_migrated');
+INSERT IGNORE INTO settings (`key`, value) VALUES ('uo_link_protocol_5_migrated', '1');
diff --git a/server/model/shardMarket/shardMarket.db.js b/server/model/shardMarket/shardMarket.db.js
index 7e33578..e631852 100644
--- a/server/model/shardMarket/shardMarket.db.js
+++ b/server/model/shardMarket/shardMarket.db.js
@@ -41,14 +41,25 @@ async function replaceVendor(vendor, items) {
 
     await conn.query(
       `INSERT INTO shard_vendors
-         (serial, shop_name, owner_serial, owner_name, map, x, y, z, region, house,
-          item_count, item_total, truncated, t)
-       VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?)
+         (serial, shop_name, owner_serial, owner_name, owner_acct, map, x, y, z, region, house,
+          item_count, item_total, truncated, t,
+          fees_exempt, charge_per_period, funds, pay_interval_sec, next_pay_at,
+          periods_remaining, dismissal_at)
+       VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)
        ON DUPLICATE KEY UPDATE shop_name = VALUES(shop_name), owner_serial = VALUES(owner_serial),
-         owner_name = VALUES(owner_name), map = VALUES(map), x = VALUES(x), y = VALUES(y),
+         owner_name = VALUES(owner_name), owner_acct = VALUES(owner_acct),
+         map = VALUES(map), x = VALUES(x), y = VALUES(y),
          z = VALUES(z), region = VALUES(region), house = VALUES(house),
          item_count = VALUES(item_count), item_total = VALUES(item_total),
          truncated = VALUES(truncated), t = VALUES(t),
+         -- Protocol 5. Written back unconditionally, INCLUDING when they are null:
+         -- a shard downgraded to a pre-v5 overlay stops sending the fees object, and
+         -- leaving the last v5 values in place would leave a dismissal date standing
+         -- that nothing is maintaining any more. A stale deadline is worse than none.
+         fees_exempt = VALUES(fees_exempt), charge_per_period = VALUES(charge_per_period),
+         funds = VALUES(funds), pay_interval_sec = VALUES(pay_interval_sec),
+         next_pay_at = VALUES(next_pay_at), periods_remaining = VALUES(periods_remaining),
+         dismissal_at = VALUES(dismissal_at),
          -- Touched explicitly rather than left to ON UPDATE CURRENT_TIMESTAMP:
          -- MariaDB does not fire that when every column is written back
          -- unchanged, and a shop that is re-published identically is still
@@ -60,6 +71,7 @@ async function replaceVendor(vendor, items) {
         vendor.shopName ?? null,
         vendor.ownerSerial ?? null,
         vendor.ownerName ?? null,
+        vendor.ownerAcct ?? null,
         vendor.map ?? null,
         Number.isFinite(vendor.x) ? vendor.x : null,
         Number.isFinite(vendor.y) ? vendor.y : null,
@@ -70,6 +82,13 @@ async function replaceVendor(vendor, items) {
         Number.isFinite(vendor.itemTotal) ? vendor.itemTotal : items.length,
         vendor.truncated ? 1 : 0,
         Number.isFinite(vendor.t) ? vendor.t : null,
+        vendor.feesExempt ? 1 : 0,
+        Number.isFinite(vendor.chargePerPeriod) ? vendor.chargePerPeriod : null,
+        Number.isFinite(vendor.funds) ? vendor.funds : null,
+        Number.isFinite(vendor.payIntervalSec) ? vendor.payIntervalSec : null,
+        vendor.nextPayAt ?? null,
+        Number.isFinite(vendor.periodsRemaining) ? vendor.periodsRemaining : null,
+        vendor.dismissalAt ?? null,
       ],
     )
 
diff --git a/server/model/shardMarket/shardMarket.model.js b/server/model/shardMarket/shardMarket.model.js
index 423fad4..9e2d818 100644
--- a/server/model/shardMarket/shardMarket.model.js
+++ b/server/model/shardMarket/shardMarket.model.js
@@ -31,6 +31,7 @@ const MAX_OWNER = 64
 const MAX_MAP = 40
 const MAX_REGION = 80
 const MAX_SERIAL = 20
+const MAX_ACCT = 120
 
 const clip = (value, max) => {
   if (value == null) return null
@@ -43,6 +44,42 @@ const int = (value, fallback = 0) => {
   return Number.isFinite(n) ? Math.trunc(n) : fallback
 }
 
+// A wire timestamp -> a Date the DB layer can bind, or null. The shard emits ISO-8601
+// (`DateTime.ToString("o")`); anything else is a plugin we do not recognise and is
+// dropped rather than stored as an Invalid Date, which MariaDB rejects in strict mode
+// and which would fail the whole vendor over one bad field.
+const when = (value) => {
+  if (!value) return null
+  const d = new Date(value)
+  return Number.isNaN(d.getTime()) ? null : d
+}
+
+// Protocol 5. The vendor's fee state, normalised out of the frame's `fees` object.
+//
+// Two things this deliberately does NOT do. It does not recompute `dismissalAt` from
+// the parts -- the shard resolved it against ServUO's own two vendor systems (the
+// charge, the funds and the interval all differ between them) and re-deriving it here
+// would be a second implementation of a rule that lives in PlayerVendor.PayTimer. And
+// it does not treat a missing `fees` object as zero: a pre-v5 overlay simply omits it,
+// and nulls are how a v5 website says "this shard has not told me" rather than
+// "this vendor is broke", which is the difference between silence and a false alarm.
+const fees = (f) => {
+  if (!f || typeof f !== 'object') return { feesExempt: false, chargePerPeriod: null, funds: null, payIntervalSec: null, nextPayAt: null, periodsRemaining: null, dismissalAt: null }
+  // A commission vendor has no pay timer and is never dismissed for fees. Reporting it
+  // as exempt with no schedule is not the same as reporting a very long one, and a
+  // surface that renders "never" must be able to tell them apart.
+  if (f.exempt === true) return { feesExempt: true, chargePerPeriod: null, funds: null, payIntervalSec: null, nextPayAt: null, periodsRemaining: null, dismissalAt: null }
+  return {
+    feesExempt: false,
+    chargePerPeriod: Number.isFinite(f.chargePerPeriod) ? Math.trunc(f.chargePerPeriod) : null,
+    funds: Number.isFinite(f.funds) ? Math.trunc(f.funds) : null,
+    payIntervalSec: Number.isFinite(f.payIntervalSec) ? Math.trunc(f.payIntervalSec) : null,
+    nextPayAt: when(f.nextPayAt),
+    periodsRemaining: Number.isFinite(f.periodsRemaining) ? Math.trunc(f.periodsRemaining) : null,
+    dismissalAt: when(f.dismissalAt),
+  }
+}
+
 // ── Ingest ─────────────────────────────────────────────────────────────────
 
 /**
@@ -64,6 +101,10 @@ function flattenFrame(ev) {
     shopName: clip(ev.shopName, MAX_SHOP),
     ownerSerial: clip(ev.ownerSerial, MAX_SERIAL),
     ownerName: clip(ev.ownerName, MAX_OWNER),
+    // Protocol 5. The character name has been here since v3, but only the game
+    // ACCOUNT joins to shard_account_links -- so this is the field that makes a
+    // vendor row resolvable to a person at all.
+    ownerAcct: clip(ev.ownerAcct, MAX_ACCT),
     map: clip(loc.map, MAX_MAP),
     x: Number.isFinite(loc.x) ? Math.trunc(loc.x) : null,
     y: Number.isFinite(loc.y) ? Math.trunc(loc.y) : null,
@@ -76,6 +117,7 @@ function flattenFrame(ev) {
     itemTotal: int(ev.total, int(ev.count, 0)),
     truncated: ev.truncated === true,
     t: Number.isFinite(ev.t) ? ev.t : null,
+    ...fees(ev.fees),
   }
 }
 
diff --git a/server/model/shardState/shardState.db.js b/server/model/shardState/shardState.db.js
index 4dbc569..9f16061 100644
--- a/server/model/shardState/shardState.db.js
+++ b/server/model/shardState/shardState.db.js
@@ -98,7 +98,12 @@ async function latestEconomy() {
 
 // ── Houses / IDOC ────────────────────────────────────────────────────────
 const HOUSE_COLS =
-  'serial, stage, map, x, y, z, region, name, owner_serial, owner_acct, built_on, last_refreshed, is_idoc, updated_at'
+  'serial, stage, map, x, y, z, region, name, owner_serial, owner_acct, built_on, last_refreshed, is_idoc, updated_at' +
+  // Protocol 5's decay schedule. Added to the BASE column list rather than to
+  // HOUSE_REG_COLS because it arrives on house.decay, so a decay-only row -- one the
+  // registry sweep has never seen -- carries it too, and the public IDOC page reads
+  // exactly those rows.
+  ', next_stage, estimated_collapse, decay_period_sec, dynamic_decay'
 
 const upsertHouse = (serial, fields) => upsertRow('shard_houses', 'serial', serial, fields)
 
diff --git a/server/model/shardState/shardState.model.js b/server/model/shardState/shardState.model.js
index 7c25254..d4d48c3 100644
--- a/server/model/shardState/shardState.model.js
+++ b/server/model/shardState/shardState.model.js
@@ -124,10 +124,39 @@ async function upsertHouse(data) {
     built_on: data.builtOn ? new Date(data.builtOn) : null,
     last_refreshed: data.lastRefreshed ? new Date(data.lastRefreshed) : null,
     is_idoc: String(data.stage).toUpperCase() === 'IDOC' ? 1 : 0,
+    // Protocol 5. `ownerName` is written back only when the frame carries one, and
+    // that asymmetry is deliberate: house.update also writes this column, from a
+    // different sweep, and a pre-v5 overlay's house.decay frame has no ownerName at
+    // all. Coalescing to null here would let every decay transition ERASE a name the
+    // registry had already resolved.
+    ...(data.ownerName ? { owner_name: String(data.ownerName).slice(0, 120) } : {}),
+    ...decayScheduleFields(data.schedule),
   }
   await db.upsertHouse(data.serial, fields)
 }
 
+// Protocol 5's `schedule` object, flattened into its columns.
+//
+// Unlike ownerName above, these are written back UNCONDITIONALLY, including as nulls.
+// A schedule is a claim about the future and it goes stale on its own: if a shard is
+// rolled back to a pre-v5 overlay, or a house leaves IDOC so its collapse time stops
+// being knowable, the right stored value is "nothing" rather than the last thing we
+// were told. A dated promise nobody is maintaining is worse than no promise.
+function decayScheduleFields(schedule) {
+  const s = schedule && typeof schedule === 'object' ? schedule : {}
+  const when = (v) => {
+    if (!v) return null
+    const d = new Date(v)
+    return Number.isNaN(d.getTime()) ? null : d
+  }
+  return {
+    next_stage: when(s.nextStage),
+    estimated_collapse: when(s.estimatedCollapse),
+    decay_period_sec: Number.isFinite(s.decayPeriodSec) ? Math.trunc(s.decayPeriodSec) : null,
+    dynamic_decay: typeof s.dynamicDecay === 'boolean' ? (s.dynamicDecay ? 1 : 0) : null,
+  }
+}
+
 function shapeHouse(r) {
   return {
     serial: r.serial,
@@ -149,6 +178,16 @@ function shapeHouse(r) {
     inRegistry: r.in_registry == null ? undefined : Boolean(r.in_registry),
     builtOn: r.built_on,
     lastRefreshed: r.last_refreshed,
+    // Protocol 5. Re-nested on read for the reason shardMarket re-nests `location`:
+    // the visibility projection matches literal JSON keys, so the stored read model
+    // and the live wire frame have to spell this the same way or the one admin rule
+    // covers only one of the two paths.
+    schedule: {
+      dynamicDecay: r.dynamic_decay == null ? null : Boolean(r.dynamic_decay),
+      nextStage: r.next_stage,
+      decayPeriodSec: r.decay_period_sec,
+      estimatedCollapse: r.estimated_collapse,
+    },
     isIdoc: Boolean(r.is_idoc),
     updatedAt: r.updated_at,
   }
diff --git a/server/model/uoLinkConfig/uoLinkConfig.model.js b/server/model/uoLinkConfig/uoLinkConfig.model.js
index 80ae4f3..fe45ddd 100644
--- a/server/model/uoLinkConfig/uoLinkConfig.model.js
+++ b/server/model/uoLinkConfig/uoLinkConfig.model.js
@@ -11,13 +11,16 @@ const { secretBox } = require('../../core')
 // Only used before an admin has saved anything — the stored row wins once it exists,
 // and UOLINK_PROTOCOL still overrides for an operator running an older sidecar.
 //
-// This says 4 because this build handles protocol 4's frames: `guild.roster` and
-// `guild.leave` ingest landed with the Teams cutover. It said 3 for a while after
-// that, which is the bug this constant is now the fix for — a FRESH install pinned
-// 3, the sidecar answered `409 protocol version mismatch` to every REST call, and a
-// new deployment read nothing from its shard until an admin edited the number by
-// hand in Admin → Shard. See the matching cutover in db/schema.sql.
-const DEFAULT_PROTOCOL = Number(process.env.UOLINK_PROTOCOL) || 4
+// This says 5 because this build handles protocol 5's frames: house.decay's `schedule`,
+// vendor.listing's `ownerAcct` + `fees`, and the new `account.login.result` kind.
+//
+// It said 4 before that, and 3 for a while after protocol 4 shipped — which is the bug
+// this constant is now the fix for. A FRESH install pinned 3, the sidecar answered
+// `409 protocol version mismatch` to every REST call, and a new deployment read nothing
+// from its shard until an admin edited the number by hand in Admin → Shard. Bumping it
+// in the SAME change as the emitters is the discipline that prevents a repeat; see the
+// matching cutover in db/schema.sql.
+const DEFAULT_PROTOCOL = Number(process.env.UOLINK_PROTOCOL) || 5
 
 function toSafe(row) {
   if (!row) {
@@ -92,4 +95,7 @@ async function recordStatus({ status, statusDetail, pluginConnected, lastEventAt
   return toSafe(row)
 }
 
-module.exports = { getSafe, getWithToken, save, recordStatus }
+// DEFAULT_PROTOCOL is exported for the schema test, which asserts that this constant
+// and schema.sql's two declarations of the same number AGREE, rather than asserting a
+// hardcoded version at each site -- which is what let them drift apart before.
+module.exports = { getSafe, getWithToken, save, recordStatus, DEFAULT_PROTOCOL }
diff --git a/server/test/schemaFragment.test.js b/server/test/schemaFragment.test.js
index 57352b4..53bd9b4 100644
--- a/server/test/schemaFragment.test.js
+++ b/server/test/schemaFragment.test.js
@@ -144,12 +144,23 @@ test('both settings seeds are INSERT IGNORE, so a replay never resets a value',
 // sidecar, which 409s every REST call — an install that reads nothing from its
 // shard, with the cause only in the log. These tests are the guard.
 
+// The protocol this build speaks, read from the model rather than written here.
+//
+// Hardcoding the number in this test is what the protocol-4 bug looked like from the
+// other side: the emitters moved, one declaration site did not, and every site agreed
+// with itself. Reading DEFAULT_PROTOCOL makes the assertion "the three declarations
+// AGREE" rather than "they all say 4", so a bump that misses one of them fails here
+// instead of on an operator's install.
+const { DEFAULT_PROTOCOL } = require('../model/uoLinkConfig/uoLinkConfig.model')
+
 test('the column default pins the protocol this build speaks', () => {
+  assert.ok(Number.isInteger(DEFAULT_PROTOCOL) && DEFAULT_PROTOCOL > 0, 'no protocol pin exported')
+
   const create = statements.find((s) => /CREATE TABLE.*uo_link_config/is.test(s))
   assert.ok(create, 'uo_link_config is gone')
   assert.match(
     create,
-    /protocol\s+INT\s+NOT NULL DEFAULT 4/i,
+    new RegExp('protocol +INT +NOT NULL DEFAULT ' + DEFAULT_PROTOCOL + '(?![0-9])', 'i'),
     'the CREATE TABLE default must name the protocol this build speaks',
   )
 
@@ -159,7 +170,34 @@ test('the column default pins the protocol this build speaks', () => {
     /^ALTER TABLE\s+uo_link_config\s+MODIFY COLUMN protocol/i.test(s),
   )
   assert.ok(modifies.length > 0, 'the default-fixing MODIFY is gone')
-  assert.match(modifies[modifies.length - 1], /DEFAULT 4/i)
+  assert.match(
+    modifies[modifies.length - 1],
+    new RegExp('DEFAULT ' + DEFAULT_PROTOCOL + '(?![0-9])', 'i'),
+  )
+})
+
+// The one-shot migration for the CURRENT protocol, whatever it is. Same argument as
+// above: these three assertions used to be written once per version by hand, so the
+// version that mattered — the newest — was the one with no test until someone
+// remembered to copy the block.
+test('the current protocol has a one-shot migration, correctly ordered and guarded', () => {
+  const marker = `uo_link_protocol_${DEFAULT_PROTOCOL}_migrated`
+
+  const update = statements.findIndex(
+    (s) => /^UPDATE\s+uo_link_config/i.test(s) && s.includes(marker),
+  )
+  const insert = statements.findIndex((s) => /^INSERT/i.test(s) && s.includes(`'${marker}'`))
+
+  assert.ok(update >= 0, `no migration to protocol ${DEFAULT_PROTOCOL}`)
+  assert.ok(insert >= 0, `no one-shot marker for protocol ${DEFAULT_PROTOCOL}`)
+  assert.ok(insert > update, 'the marker is written before the UPDATE reads it')
+
+  // `protocol < N`, never `= N-1`: an install that missed an earlier migration has to
+  // be carried the whole way rather than one step.
+  assert.match(
+    statements[update],
+    new RegExp('protocol *< *' + DEFAULT_PROTOCOL + '(?![0-9])'),
+  )
 })
 
 test('the protocol-4 marker is written AFTER the update that reads it', () => {
diff --git a/server/test/shardMarket.model.test.js b/server/test/shardMarket.model.test.js
index 70c18c9..702337b 100644
--- a/server/test/shardMarket.model.test.js
+++ b/server/test/shardMarket.model.test.js
@@ -261,3 +261,91 @@ test('the cliloc resolver is the path shapeItems resolves through', async () =>
   const found = await clilocs.resolveMany([1023721])
   assert.equal(found.get(1023721), 'quarter staff')
 })
+
+// ── Protocol 5: owner account and fee state ────────────────────────────────
+
+const V5_FEES = {
+  exempt: false,
+  newVendorSystem: true,
+  chargePerPeriod: 148,
+  funds: 2960,
+  holdGold: 2960,
+  bankAccount: 0,
+  payIntervalSec: 86400,
+  nextPayAt: '2026-09-01T00:00:00.000Z',
+  periodsRemaining: 20,
+  dismissalAt: '2026-09-21T00:00:00.000Z',
+}
+
+test('flattenFrame lifts ownerAcct, the field that makes a shop resolvable to a person', () => {
+  // ownerName has been on the frame since v3, but a character name joins to nothing:
+  // shard_account_links is keyed by the game ACCOUNT.
+  const row = market.flattenFrame({ ...FRAME, ownerAcct: 'darrow_acct', fees: V5_FEES })
+  assert.equal(row.ownerAcct, 'darrow_acct')
+  assert.equal(row.ownerName, 'Darrow', 'the character name is still carried too')
+})
+
+test('flattenFrame normalises the fee block, dates included', () => {
+  const row = market.flattenFrame({ ...FRAME, fees: V5_FEES })
+  assert.equal(row.feesExempt, false)
+  assert.equal(row.chargePerPeriod, 148)
+  assert.equal(row.funds, 2960)
+  assert.equal(row.payIntervalSec, 86400)
+  assert.equal(row.periodsRemaining, 20)
+  assert.ok(row.nextPayAt instanceof Date)
+  assert.equal(row.dismissalAt.toISOString(), '2026-09-21T00:00:00.000Z')
+})
+
+// The shard resolved dismissalAt against ServUO's two vendor systems, whose charge,
+// funds and pay interval all differ. Re-deriving it here would be a second
+// implementation of a rule that lives in PlayerVendor.PayTimer.
+test('flattenFrame trusts the shard dismissal date instead of recomputing it', () => {
+  const row = market.flattenFrame({
+    ...FRAME,
+    fees: { ...V5_FEES, dismissalAt: '2026-12-25T00:00:00.000Z' },
+  })
+  assert.equal(row.dismissalAt.toISOString(), '2026-12-25T00:00:00.000Z')
+})
+
+// A commission vendor has no pay timer and is never dismissed for fees. That is a
+// different thing from having a long time left, and a surface rendering "never" has
+// to be able to tell them apart.
+test('an exempt vendor reports exempt with no schedule at all', () => {
+  const row = market.flattenFrame({ ...FRAME, fees: { exempt: true } })
+  assert.equal(row.feesExempt, true)
+  assert.equal(row.dismissalAt, null)
+  assert.equal(row.periodsRemaining, null)
+  assert.equal(row.chargePerPeriod, null)
+})
+
+// A pre-v5 overlay omits `fees` entirely, and a shard can be rolled back to one.
+// Nulls have to mean "this shard has not told me", never "this vendor is broke" —
+// the difference between silence and a false alarm in a rule that mails an owner.
+test('a pre-v5 frame yields nulls, not zeroes', () => {
+  const row = market.flattenFrame(FRAME)
+  assert.equal(row.feesExempt, false)
+  for (const key of ['chargePerPeriod', 'funds', 'payIntervalSec', 'periodsRemaining']) {
+    assert.equal(row[key], null, `${key} must be null, not 0`)
+  }
+  assert.equal(row.nextPayAt, null)
+  assert.equal(row.dismissalAt, null)
+  assert.equal(row.ownerAcct, null)
+})
+
+test('an unparseable fee date is dropped rather than stored as an Invalid Date', () => {
+  const row = market.flattenFrame({
+    ...FRAME,
+    fees: { ...V5_FEES, dismissalAt: 'next tuesday', nextPayAt: null },
+  })
+  assert.equal(row.dismissalAt, null)
+  assert.equal(row.nextPayAt, null)
+  assert.equal(row.funds, 2960, 'one bad field must not discard the rest of the block')
+})
+
+test('a malformed fees value is treated as absent, not as a crash', () => {
+  for (const fees of ['', 0, 'nope', []]) {
+    const row = market.flattenFrame({ ...FRAME, fees })
+    assert.equal(row.feesExempt, false)
+    assert.equal(row.dismissalAt, null)
+  }
+})
diff --git a/server/test/shardState.model.test.js b/server/test/shardState.model.test.js
index 1b439e7..8428289 100644
--- a/server/test/shardState.model.test.js
+++ b/server/test/shardState.model.test.js
@@ -251,3 +251,74 @@ test('listGovernorHistory coerces started/ended timestamps to numbers and clamps
   assert.equal(typeof out[0].startedAt, 'number')
   assert.equal(out[0].endedAt, null) // an open term stays null, not coerced to 0
 })
+
+// ── Protocol 5: the decay schedule ─────────────────────────────────────────
+
+test('upsertHouse flattens the nested schedule into its four columns', async () => {
+  await shardState.upsertHouse({
+    serial: 1,
+    stage: 'IDOC',
+    schedule: {
+      dynamicDecay: true,
+      nextStage: '2026-09-02T04:00:00.000Z',
+      decayPeriodSec: 432000,
+      estimatedCollapse: '2026-09-02T04:00:00.000Z',
+    },
+  })
+  const [, fields] = calls.upsertHouse[0]
+  assert.equal(fields.dynamic_decay, 1)
+  assert.equal(fields.decay_period_sec, 432000)
+  assert.ok(fields.next_stage instanceof Date)
+  assert.equal(fields.estimated_collapse.toISOString(), '2026-09-02T04:00:00.000Z')
+})
+
+// The whole point of the field: under dynamic decay ServUO draws each stage's
+// duration at random on entry, so the shard omits estimatedCollapse everywhere but
+// IDOC. A stored null has to mean "not knowable", which it cannot if a partial
+// schedule silently keeps the previous value.
+test('a schedule without a collapse time stores null, it does not keep the old one', async () => {
+  await shardState.upsertHouse({
+    serial: 1,
+    stage: 'Greatly',
+    schedule: { dynamicDecay: true, nextStage: '2026-09-01T00:00:00.000Z', decayPeriodSec: 432000 },
+  })
+  const [, fields] = calls.upsertHouse[0]
+  assert.equal(fields.estimated_collapse, null)
+  assert.ok('estimated_collapse' in fields, 'must be WRITTEN as null, not omitted')
+})
+
+// A pre-v5 overlay sends no schedule at all, and a shard can be rolled back to one.
+// Every column is still written, so a dismissal date nobody is maintaining cannot
+// be left standing.
+test('a frame with no schedule nulls all four columns rather than omitting them', async () => {
+  await shardState.upsertHouse({ serial: 1, stage: 'Fairly' })
+  const [, fields] = calls.upsertHouse[0]
+  for (const col of ['next_stage', 'estimated_collapse', 'decay_period_sec', 'dynamic_decay']) {
+    assert.ok(col in fields, `${col} must be written`)
+    assert.equal(fields[col], null)
+  }
+})
+
+test('an unparseable schedule date is dropped, not stored as an Invalid Date', async () => {
+  await shardState.upsertHouse({
+    serial: 1,
+    stage: 'IDOC',
+    schedule: { nextStage: 'soon-ish', estimatedCollapse: '' },
+  })
+  const [, fields] = calls.upsertHouse[0]
+  assert.equal(fields.next_stage, null)
+  assert.equal(fields.estimated_collapse, null)
+})
+
+// house.update writes owner_name from its own sweep. If house.decay coalesced a
+// missing ownerName to null, every decay transition on a pre-v5 shard would erase
+// a name the registry had already resolved.
+test('house.decay never erases an owner_name it was not given', async () => {
+  await shardState.upsertHouse({ serial: 1, stage: 'IDOC', ownerAcct: 'cadmus' })
+  const [, fields] = calls.upsertHouse[0]
+  assert.ok(!('owner_name' in fields), 'owner_name must not be written when absent')
+
+  await shardState.upsertHouse({ serial: 1, stage: 'IDOC', ownerName: 'Cadmus' })
+  const [, withName] = calls.upsertHouse[1]
+  assert.equal(withName.owner_name, 'Cadmus')
+})
diff --git a/server/test/shardVisibility.test.js b/server/test/shardVisibility.test.js
index 3e53c80..771e874 100644
--- a/server/test/shardVisibility.test.js
+++ b/server/test/shardVisibility.test.js
@@ -476,3 +476,109 @@ test('a link lookup failure downgrades rather than escalating', async () => {
   visibility.forgetUser(6)
   assert.equal(await visibility.viewerLevel({ user: { id: 6, role: 'player' } }), 'logged_in')
 })
+
+// ── Protocol 5 ─────────────────────────────────────────────────────────────
+//
+// Two new nested field groups and one new kind. All three exist as visibility
+// questions before they exist as features, which is the order this framework's
+// rule 2 is designed to force: a v5 field that nobody classified would either
+// leak (if it fell open) or be silently invisible (if it fell closed and nobody
+// noticed). These tests pin the three answers that were actually chosen.
+
+test('a vendor fee block is admin-only, and it is the whole block', async () => {
+  const config = await visibility.getConfig()
+  // The frame as BridgeMarket emits it: the shop's public parts, plus the money.
+  const frame = {
+    serial: '0x40001234',
+    shopName: "Darrow's Bargains",
+    ownerName: 'Darrow',
+    location: { map: 'Trammel', x: 1421, y: 1699, region: 'Britain' },
+    fees: {
+      exempt: false,
+      chargePerPeriod: 148,
+      funds: 2960,
+      periodsRemaining: 20,
+      dismissalAt: '2026-09-20T00:00:00.0000000Z',
+    },
+  }
+
+  for (const level of ['anonymous', 'logged_in', 'player', 'staff']) {
+    const out = visibility.projectFeature('market', frame, level, config)
+    assert.equal('fees' in out, false, `fees reached ${level}`)
+    // The rest of the shop is untouched — this is a field rule, not a feature one.
+    assert.equal(out.shopName, "Darrow's Bargains", `${level} lost the shop name`)
+    assert.equal(out.location.region, 'Britain', `${level} lost the location`)
+  }
+
+  const asAdmin = visibility.projectFeature('market', frame, 'admin', config)
+  assert.equal(asAdmin.fees.funds, 2960)
+  assert.equal(asAdmin.fees.dismissalAt, '2026-09-20T00:00:00.0000000Z')
+})
+
+// The nesting is the point, not a style choice: projectValue matches literal JSON
+// keys, so seven flat fee keys would be seven rules an admin has to keep in step
+// and a v6 field would default to visible. One nested key cannot drift.
+test('the fee rule is one nested key, so a new fee field inherits the gate', async () => {
+  const config = await visibility.getConfig()
+  const frame = { serial: '0x1', fees: { exempt: false, somethingAddedLater: 'secret' } }
+  const out = visibility.projectFeature('market', frame, 'staff', config)
+  assert.equal('fees' in out, false, 'a field added inside fees must not fall out of the gate')
+})
+
+// The opposite call, and it is deliberate: the decay countdown is the public IDOC
+// page's entire content, and a house at IDOC is already announced in game.
+test('the decay schedule is anonymous by default but remains configurable', async () => {
+  const frame = {
+    serial: '0x1',
+    to: 'IDOC',
+    name: 'Marble Tower',
+    schedule: {
+      dynamicDecay: true,
+      nextStage: '2026-09-02T04:00:00.0000000Z',
+      decayPeriodSec: 432000,
+      estimatedCollapse: '2026-09-02T04:00:00.0000000Z',
+    },
+  }
+
+  const config = await visibility.getConfig()
+  const anon = visibility.projectFeature('houses', frame, 'anonymous', config)
+  assert.equal(anon.schedule.estimatedCollapse, '2026-09-02T04:00:00.0000000Z')
+
+  // A shard that considers a precise collapse time an unfair advantage can raise it,
+  // and raising the one nested rule takes the whole schedule with it.
+  withRows([
+    {
+      feature: 'houses',
+      enabled: true,
+      audience: 'anonymous',
+      stream: true,
+      fieldRules: { schedule: 'staff' },
+    },
+  ])
+  const tightened = await visibility.getConfig()
+  assert.equal('schedule' in visibility.projectFeature('houses', frame, 'player', tightened), false)
+  assert.equal(
+    visibility.projectFeature('houses', frame, 'staff', tightened).schedule.decayPeriodSec,
+    432000,
+  )
+  // Tightening the schedule must not have disturbed the owner rules beside it.
+  assert.equal(visibility.projectFeature('houses', frame, 'anonymous', tightened).name, 'Marble Tower')
+})
+
+// Rule 2, exercised on the kind it was added for. account.login.result says whether
+// a password was accepted and from which IP; it is admin-only by OMISSION, and the
+// omission is the decision. If someone maps it to a feature to "make it visible",
+// this fails and says why.
+test('account.login.result is admin-only, like the attempt it completes', async () => {
+  const config = await visibility.getConfig()
+  assert.equal(
+    visibility.KIND_FEATURE.has('account.login.result'),
+    false,
+    'mapping this kind to a feature would let an admin widen an IP + auth verdict below admin',
+  )
+  for (const level of ['anonymous', 'logged_in', 'player', 'staff']) {
+    assert.equal(visibility.kindVisibleTo('account.login.result', level, config), false)
+  }
+  assert.equal(visibility.kindVisibleTo('account.login.result', 'admin', config), true)
+  assert.equal(visibility.PUBLIC_KINDS.has('account.login.result'), false)
+})
diff --git a/server/utils/shardIngest.js b/server/utils/shardIngest.js
index b21f6f1..62ad8a1 100644
--- a/server/utils/shardIngest.js
+++ b/server/utils/shardIngest.js
@@ -169,8 +169,14 @@ async function applyStateChange(event, deps) {
         name: event.name,
         ownerSerial: event.ownerSerial,
         ownerAcct: event.ownerAcct,
+        // Protocol 5. `ownerName` used to arrive only on house.update, so a house
+        // that had decayed but never been swept into the registry named an account
+        // and no character. It rides house.decay now, which is the frame the IDOC
+        // page is actually built from.
+        ownerName: event.ownerName,
         builtOn: event.builtOn,
         lastRefreshed: event.lastRefreshed,
+        schedule: event.schedule,
       })
       return
     case 'champ.update':
diff --git a/server/utils/shardVisibility.js b/server/utils/shardVisibility.js
index a098569..8f50510 100644
--- a/server/utils/shardVisibility.js
+++ b/server/utils/shardVisibility.js
@@ -91,9 +91,22 @@ const FEATURES = {
   // `ownerName`/`ownerSerial` are the flattened spellings shapeHouse emits on the
   // REST read models. Both are listed so one rule covers the wire and the read
   // model — the flattened `ownerAcct` needs no entry, being locked by rule 1.
+  // Protocol 5 adds `schedule` — when the next stage lands and, where ServUO can
+  // actually know it, when the house collapses. It defaults to `anonymous` because
+  // that is what the public IDOC page is FOR: the countdown is the content, and a
+  // house at IDOC is already announced in game. It is listed rather than left
+  // unconfigurable so a shard that considers a precise collapse time an unfair
+  // advantage can raise it, and it is one NESTED key so raising it hides the whole
+  // schedule rather than three of its four parts.
   houses: {
     audience: 'anonymous',
-    fields: { owner: 'staff', ownerName: 'staff', ownerSerial: 'staff', price: 'staff' },
+    fields: {
+      owner: 'staff',
+      ownerName: 'staff',
+      ownerSerial: 'staff',
+      price: 'staff',
+      schedule: 'anonymous',
+    },
   },
   // /public/shard/online listed linked staff to everyone but gated location to
   // admin+moderator — which is exactly the `staff` rung.
@@ -124,9 +137,25 @@ const FEATURES = {
   // `ownerSerial` is listed alongside `ownerName` for the same reason `houses`
   // lists both: an admin who hides the owner's name and is left with a serial
   // that every other board resolves back to that name has not hidden anything.
+  // Protocol 5 adds `fees`, and it does NOT follow the rest of this feature's
+  // defaults. The shop name, the owner and the location are already visible to any
+  // player through the stock in-game Vendor Search gump, which is the whole argument
+  // for publishing them. A vendor's held gold, daily charge and dismissal date are
+  // not: in game they are visible to the OWNER, on that vendor's own gump. Publishing
+  // them anonymously would be a genuinely new disclosure and a targeting aid — it
+  // says which shops are about to be abandoned and how much coin is sitting in each.
+  // So it defaults to `admin`, the only default here that does not reproduce prior
+  // behaviour, because there is no prior behaviour to reproduce.
+  //
+  // Nested for the same reason `location` is: one rule covers all seven parts.
   market: {
     audience: 'anonymous',
-    fields: { ownerName: 'anonymous', ownerSerial: 'anonymous', location: 'anonymous' },
+    fields: {
+      ownerName: 'anonymous',
+      ownerSerial: 'anonymous',
+      location: 'anonymous',
+      fees: 'admin',
+    },
   },
 }
 
@@ -177,6 +206,13 @@ const KIND_FEATURE = new Map(
     // registry (house.update / house.remove — owner, price, co-owners) stays
     // off the map deliberately, so it remains admin-only exactly as before.
     'house.decay': 'houses',
+    // Protocol 5's `account.login.result` is deliberately NOT here, and the omission
+    // is the decision rather than an oversight. Rule 2 fails an unmapped kind closed
+    // to admin-only, which is the right answer for a frame that carries an IP address
+    // and says whether a password was accepted — the same reasoning that keeps
+    // house.update and account.login.attempt off this map. Adding it would mean
+    // choosing a feature an admin could then widen, and there is no rung below admin
+    // this frame belongs on.
     // v3
     'world.ruleset': 'ruleset',
     'points.board': 'leaderboards',