diff --git a/apps/hq/scripts/migrate-onboarding-templates.ts b/apps/hq/scripts/migrate-onboarding-templates.ts
new file mode 100644
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+++ b/apps/hq/scripts/migrate-onboarding-templates.ts
@@ -0,0 +1,19 @@
+// apps/hq/scripts/migrate-onboarding-templates.ts — Client Detail redesign task 5: one-time
+// migration swapping existing SMS/RTGS/MobileApp projects off the old generic onboarding
+// checklist onto their new per-module template, carrying mapped ticks. Idempotent — safe
+// to re-run (a second run does nothing).
+//   DATABASE_URL=postgres://… npx tsx apps/hq/scripts/migrate-onboarding-templates.ts
+import { openDb } from '../src/db'
+import { openPgDb } from '../src/db-pg'
+import { migrateOnboardingTemplates } from '../src/migrate-onboarding-templates'
+
+async function main() {
+  const pgUrl = process.env['DATABASE_URL'] ?? ''
+  const db = pgUrl !== '' ? await openPgDb(pgUrl) : openDb(process.env['HQ_DATA_DIR'])
+
+  const res = await migrateOnboardingTemplates(db)
+  // eslint-disable-next-line no-console
+  console.log(`Onboarding template migration: ${res.projects} project(s) rebuilt, ${res.carried} tick(s) carried, ${res.dropped} dropped.`)
+}
+
+main().catch((e) => { console.error(e); process.exit(1) })
diff --git a/apps/hq/src/migrate-onboarding-templates.ts b/apps/hq/src/migrate-onboarding-templates.ts
new file mode 100644
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+++ b/apps/hq/src/migrate-onboarding-templates.ts
@@ -0,0 +1,81 @@
+// apps/hq/src/migrate-onboarding-templates.ts — Client Detail redesign task 5: one-time
+// migration swapping seeded modules (SMS/RTGS/MobileApp) off the old generic onboarding
+// checklist onto their new per-module template (task 2), carrying mapped ticks
+// (done + done_on + payment_id) so onboarding history is not lost.
+import { uuidv7 } from '@sims/domain'
+import { writeAudit } from './audit'
+import { milestoneTemplate } from './repos-milestones'
+import type { DB } from './db'
+
+/** old generic key -> new template key (only applied if the new template has that key). */
+const KEY_MAP: Record<string, string> = {
+  installed: 'installation', go_live: 'go_live',
+  advance_paid: 'advance_payment', balance_paid: 'balance_payment',
+  setup_done: 'setup_configuration',
+}
+
+interface OldRow { key: string; done: number; done_on: string | null; payment_id: string | null }
+
+/**
+ * Idempotent: for every client_module whose module has a per-module onboarding template
+ * (a `project.milestone_template:<CODE>` setting — task 2), rebuild its milestone rows
+ * from that template, carrying mapped ticks (done/done_on/payment_id) forward under their
+ * new key. Unmapped old ticks (e.g. `amc_start`, or `setup_done` for a module whose new
+ * template has no matching step) are dropped (and counted). Client_modules whose module
+ * has no per-module template are left completely untouched.
+ */
+export async function migrateOnboardingTemplates(
+  db: DB,
+): Promise<{ projects: number; carried: number; dropped: number }> {
+  // Which module codes have a per-module template setting?
+  const codes = (await db.all<{ key: string }>(
+    `SELECT key FROM setting WHERE key LIKE 'project.milestone_template:%'`))
+    .map((r) => r.key.slice('project.milestone_template:'.length))
+  let projects = 0, carried = 0, dropped = 0
+  for (const code of codes) {
+    const template = await milestoneTemplate(db, code)
+    const templateKeys = new Set(template.map((t) => t.key))
+    const cms = await db.all<{ id: string }>(
+      `SELECT cm.id FROM client_module cm JOIN module m ON m.id = cm.module_id WHERE m.code=?`, code)
+    for (const { id: cmId } of cms) {
+      const oldRows = await db.all<OldRow>(
+        `SELECT key, done, done_on, payment_id FROM project_milestone WHERE client_module_id=?`, cmId)
+      // Build the carried tick-state keyed by NEW key.
+      const carriedState = new Map<string, OldRow>()
+      let alreadyNew = true
+      for (const r of oldRows) {
+        if (!templateKeys.has(r.key)) alreadyNew = false
+        const target = templateKeys.has(r.key) ? r.key : KEY_MAP[r.key]
+        if (target !== undefined && templateKeys.has(target)) {
+          if (r.done === 1) carriedState.set(target, r)
+        } else if (r.done === 1) {
+          dropped++
+        }
+      }
+      // Idempotency: if the project's keys already ARE exactly the template, skip.
+      const oldKeySet = new Set(oldRows.map((r) => r.key))
+      const identical = alreadyNew && oldKeySet.size === templateKeys.size
+        && [...templateKeys].every((k) => oldKeySet.has(k))
+      if (identical) continue
+      projects++
+      await db.transaction(async () => {
+        await db.run(`DELETE FROM project_milestone WHERE client_module_id=?`, cmId)
+        let sort = 0
+        for (const t of template) {
+          const c = carriedState.get(t.key)
+          await db.run(
+            `INSERT INTO project_milestone (id, client_module_id, key, label, done, done_on, payment_id, sort)
+             VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
+            uuidv7(), cmId, t.key, t.label,
+            c !== undefined ? 1 : 0, c?.done_on ?? null, c?.payment_id ?? null, sort,
+          )
+          if (c !== undefined) carried++
+          sort++
+        }
+        await writeAudit(db, 'system', 'migrate_onboarding', 'client_module', cmId, undefined,
+          { module: code, carried: [...carriedState.keys()] })
+      })
+    }
+  }
+  return { projects, carried, dropped }
+}
diff --git a/apps/hq/test/migrate-onboarding-templates.test.ts b/apps/hq/test/migrate-onboarding-templates.test.ts
new file mode 100644
index 0000000..6d34d15
--- /dev/null
+++ b/apps/hq/test/migrate-onboarding-templates.test.ts
@@ -0,0 +1,141 @@
+// apps/hq/test/migrate-onboarding-templates.test.ts — Client Detail redesign task 5: one-time
+// migration swapping seeded modules (SMS/RTGS/MobileApp) from the old generic onboarding
+// checklist onto their new per-module templates, carrying mapped ticks (done/done_on/payment_id).
+import { describe, it, expect, beforeEach } from 'vitest'
+import { openDb, type DB } from '../src/db'
+import { seedIfEmpty } from '../src/seed'
+import { createClient } from '../src/repos-clients'
+import { createModule, assignModule } from '../src/repos-modules'
+import { migrateOnboardingTemplates } from '../src/migrate-onboarding-templates'
+import { listProjectMilestones } from '../src/repos-milestones'
+
+describe('onboarding template migration', () => {
+  let db: DB
+  beforeEach(async () => { db = openDb(':memory:'); await seedIfEmpty(db) })
+
+  async function makeSmsClientModule(): Promise<string> {
+    const client = await createClient(db, 'u1', { name: 'Kothavara SCB', stateCode: '32' })
+    const mod = await createModule(db, 'u1', { code: 'SMS', name: 'Bulk SMS' })
+    const cm = await assignModule(db, 'u1', { clientId: client.id, moduleId: mod.id, kind: 'yearly' })
+    // assignModule auto-seeds the NEW per-module template (task 2/4) — wipe it so the test
+    // can plant the OLD generic rows a legacy project would actually have on disk.
+    await db.run(`DELETE FROM project_milestone WHERE client_module_id=?`, cm.id)
+    return cm.id
+  }
+
+  async function seedOldGenericRows(cmId: string): Promise<void> {
+    const rows: [string, number, string | null][] = [
+      ['advance_paid', 0, null], ['setup_done', 0, null], ['installed', 1, '2026-03-25'],
+      ['go_live', 1, '2026-04-02'], ['balance_paid', 0, null], ['amc_start', 0, null],
+    ]
+    for (const [i, r] of rows.entries()) {
+      await db.run(
+        `INSERT INTO project_milestone (id,client_module_id,key,label,done,done_on,sort)
+         VALUES (?,?,?,?,?,?,?)`,
+        `m${i}`, cmId, r[0], String(r[0]), r[1], r[2], i,
+      )
+    }
+  }
+
+  it('swaps an SMS project to the 9-step list carrying installed+go_live ticks', async () => {
+    const cmId = await makeSmsClientModule()
+    await seedOldGenericRows(cmId)
+
+    const res = await migrateOnboardingTemplates(db)
+    expect(res.projects).toBe(1)
+    expect(res.carried).toBe(2) // installed -> installation, go_live -> go_live
+    expect(res.dropped).toBe(0) // the two dropped keys (setup_done, amc_start) were both undone
+
+    const ms = await listProjectMilestones(db, cmId)
+    expect(ms.map((m) => m.key)).toEqual([
+      'document_collection', 'dlt_registration', 'account_creation', 'installation',
+      'testing', 'training', 'go_live', 'advance_payment', 'balance_payment',
+    ])
+    const installation = ms.find((m) => m.key === 'installation')!
+    expect(installation.done).toBe(true)
+    expect(installation.doneOn).toBe('2026-03-25')
+    expect(installation.paymentId).toBeNull()
+    const goLive = ms.find((m) => m.key === 'go_live')!
+    expect(goLive.done).toBe(true)
+    expect(goLive.doneOn).toBe('2026-04-02')
+    // untouched (never ticked) steps stay pending
+    expect(ms.find((m) => m.key === 'document_collection')!.done).toBe(false)
+    expect(ms.find((m) => m.key === 'advance_payment')!.done).toBe(false)
+    expect(ms.find((m) => m.key === 'balance_payment')!.done).toBe(false)
+    // old setup_done / amc_start gone entirely
+    expect(ms.some((m) => m.key === 'setup_done' || m.key === 'amc_start')).toBe(false)
+
+    // audited
+    const audits = await db.all<{ entity_id: string; after_json: string | null }>(
+      `SELECT entity_id, after_json FROM audit_log WHERE action='migrate_onboarding'`,
+    )
+    expect(audits).toHaveLength(1)
+    expect(audits[0]!.entity_id).toBe(cmId)
+    expect(audits[0]!.after_json).toContain('installation')
+  })
+
+  it('carries a done payment_id along with the mapped tick', async () => {
+    const cmId = await makeSmsClientModule()
+    const client = await db.get<{ client_id: string }>(
+      `SELECT client_id FROM client_module WHERE id=?`, cmId,
+    )
+    const paymentId = 'pay-1'
+    await db.run(
+      `INSERT INTO payment (id, client_id, received_on, mode, amount_paise, created_by, created_at)
+       VALUES (?, ?, '2026-03-01', 'bank', 500000, 'u1', '2026-03-01T00:00:00.000Z')`,
+      paymentId, client!.client_id,
+    )
+    await db.run(
+      `INSERT INTO project_milestone (id, client_module_id, key, label, done, done_on, payment_id, sort)
+       VALUES (?,?,?,?,?,?,?,?)`,
+      'm0', cmId, 'advance_paid', 'advance_paid', 1, '2026-03-01', paymentId, 0,
+    )
+
+    await migrateOnboardingTemplates(db)
+    const ms = await listProjectMilestones(db, cmId)
+    const advance = ms.find((m) => m.key === 'advance_payment')!
+    expect(advance.done).toBe(true)
+    expect(advance.doneOn).toBe('2026-03-01')
+    expect(advance.paymentId).toBe(paymentId)
+  })
+
+  it('is idempotent (second run changes nothing new)', async () => {
+    const cmId = await makeSmsClientModule()
+    await seedOldGenericRows(cmId)
+
+    const first = await migrateOnboardingTemplates(db)
+    expect(first.projects).toBe(1)
+    const afterFirst = await listProjectMilestones(db, cmId)
+
+    const second = await migrateOnboardingTemplates(db)
+    expect(second.projects).toBe(0)
+    expect(second.carried).toBe(0)
+    expect(second.dropped).toBe(0)
+    const afterSecond = await listProjectMilestones(db, cmId)
+    expect(afterSecond).toEqual(afterFirst)
+
+    // no extra audit rows written on the no-op second pass
+    const audits = await db.all<{ n: number }>(
+      `SELECT COUNT(*) AS n FROM audit_log WHERE action='migrate_onboarding'`,
+    )
+    expect((audits[0] as unknown as { n: number }).n).toBe(1)
+  })
+
+  it('leaves a module without a per-module template untouched', async () => {
+    const client = await createClient(db, 'u1', { name: 'Other Society', stateCode: '32' })
+    const mod = await createModule(db, 'u1', { code: 'NOTEMPLATE', name: 'No Template Module' })
+    const cm = await assignModule(db, 'u1', { clientId: client.id, moduleId: mod.id, kind: 'yearly' })
+    // This module has no project.milestone_template:NOTEMPLATE setting, so ensureProjectMilestones
+    // fell back to the global generic template — the OLD generic rows themselves.
+    const before = await listProjectMilestones(db, cm.id)
+    expect(before.map((m) => m.key)).toEqual([
+      'advance_paid', 'setup_done', 'installed', 'go_live', 'balance_paid', 'amc_start',
+    ])
+
+    const res = await migrateOnboardingTemplates(db)
+    expect(res.projects).toBe(0)
+
+    const after = await listProjectMilestones(db, cm.id)
+    expect(after).toEqual(before)
+  })
+})