diff --git a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/invoice-lifecycle/__tests__/index.test.ts b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/invoice-lifecycle/__tests__/index.test.ts
index 7630f258..e3fda871 100644
--- a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/invoice-lifecycle/__tests__/index.test.ts
+++ b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/invoice-lifecycle/__tests__/index.test.ts
@@ -61,7 +61,7 @@ const BASE_ORDER = {
     is_internal: false,
 }
 
-const CONFERENCE = { id: 'conf-1', title: 'programmier.con 2026', start_on: '2026-03-01' }
+const CONFERENCE = { id: 'conf-1', title: 'programmier.con 2026', start_on: '2026-03-01', end_on: '2026-03-02' }
 
 const ORIGINAL_SNAPSHOT = {
     order_id: 'order-1',
@@ -386,6 +386,11 @@ describe('invoice-lifecycle endpoint', () => {
             })
             // Snapshot taken from the order's CURRENT billing data.
             expect(correction.snapshot_json.company_name).toBe('Beispiel GmbH')
+            // Same service as the original: Leistungsdatum from the conference dates.
+            expect(correction.snapshot_json).toMatchObject({
+                service_date_start: '2026-03-01',
+                service_date_end: '2026-03-02',
+            })
 
             // The original document row stays byte-for-byte untouched.
             const original = db.ticket_invoices.find((r) => r.id === 'doc-original')
@@ -495,6 +500,9 @@ describe('invoice-lifecycle endpoint', () => {
                 vat_amount_cents: -3610,
                 total_gross_cents: -22610,
                 ticket_count: 2,
+                // The referenced snapshot predates the Leistungsdatum: falls back to the conference dates.
+                service_date_start: '2026-03-01',
+                service_date_end: '2026-03-02',
             })
 
             // The original document row stays untouched, nothing is deleted.
diff --git a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/invoice-lifecycle/index.ts b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/invoice-lifecycle/index.ts
index b444dd64..9fe053b5 100644
--- a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/invoice-lifecycle/index.ts
+++ b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/invoice-lifecycle/index.ts
@@ -12,8 +12,10 @@ import {
     negateInvoiceSnapshot,
     parseInvoiceSnapshot,
     renderAndUploadInvoice,
+    withServicePeriod,
     type InvoiceDocument,
     type RenderInvoiceResult,
+    type ServicePeriod,
 } from '../shared/invoice-service.js'
 import { invoiceFilesFolder } from '../shared/secure-invoice-folder.js'
 
@@ -50,6 +52,7 @@ const ORDER_FIELDS = [
 interface OrderContext {
     order: any
     conference: any
+    servicePeriod: ServicePeriod
     ticketCount: number
     documents: InvoiceDocument[]
     currentDocument: InvoiceDocument | null
@@ -138,7 +141,9 @@ export default defineEndpoint(async (router: SandboxEndpointRouter, context) =>
         }
 
         const conferencesService = new ItemsService('conferences', { schema, accountability })
-        const conference = await conferencesService.readOne(order.conference, { fields: ['title', 'start_on'] })
+        const conference = await conferencesService.readOne(order.conference, {
+            fields: ['title', 'start_on', 'end_on'],
+        })
 
         if (!conference) {
             throw new HttpError(400, `Conference ${order.conference} not found`)
@@ -151,11 +156,14 @@ export default defineEndpoint(async (router: SandboxEndpointRouter, context) =>
             )
         }
 
+        const servicePeriod: ServicePeriod = { start_on: conference.start_on, end_on: conference.end_on }
+
         let documents: InvoiceDocument[]
         try {
             documents = await ensureInvoiceDocuments({
                 order,
                 conferenceTitle: conference.title,
+                servicePeriod,
                 ticketCount,
                 invoicesService,
             })
@@ -171,6 +179,7 @@ export default defineEndpoint(async (router: SandboxEndpointRouter, context) =>
         return {
             order,
             conference,
+            servicePeriod,
             ticketCount,
             documents,
             currentDocument: findCurrentInvoiceDocument(documents),
@@ -244,7 +253,7 @@ export default defineEndpoint(async (router: SandboxEndpointRouter, context) =>
             throw new HttpError(400, `Invoice ${current.invoice_number} has been cancelled`)
         }
 
-        const snapshot = buildInvoiceSnapshot(ctx.order, ctx.conference.title, ctx.ticketCount)
+        const snapshot = buildInvoiceSnapshot(ctx.order, ctx.conference.title, ctx.ticketCount, ctx.servicePeriod)
 
         let rendered: RenderInvoiceResult
         if (current.type === 'correction') {
@@ -326,7 +335,7 @@ export default defineEndpoint(async (router: SandboxEndpointRouter, context) =>
         const invoiceNumber = await generateInvoiceNumber(ctx.ordersService, ctx.invoicesService, conferenceYear)
         const invoiceDate = new Date()
 
-        const snapshot = buildInvoiceSnapshot(ctx.order, ctx.conference.title, ctx.ticketCount)
+        const snapshot = buildInvoiceSnapshot(ctx.order, ctx.conference.title, ctx.ticketCount, ctx.servicePeriod)
         const rendered = await renderAndUploadInvoice({
             snapshot,
             invoiceNumber,
@@ -407,7 +416,9 @@ export default defineEndpoint(async (router: SandboxEndpointRouter, context) =>
         const invoiceNumber = await generateInvoiceNumber(ctx.ordersService, ctx.invoicesService, conferenceYear)
         const invoiceDate = new Date()
 
-        const snapshot = negateInvoiceSnapshot(referencedSnapshot)
+        // Same service as the referenced invoice, so the same Leistungsdatum; snapshots
+        // written before it was recorded fall back to the conference dates.
+        const snapshot = negateInvoiceSnapshot(withServicePeriod(referencedSnapshot, ctx.servicePeriod))
 
         const rendered = await renderAndUploadInvoice({
             snapshot,
diff --git a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/__tests__/invoice-generator.test.ts b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/__tests__/invoice-generator.test.ts
index b6133816..42a72ae7 100644
--- a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/__tests__/invoice-generator.test.ts
+++ b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/__tests__/invoice-generator.test.ts
@@ -4,10 +4,12 @@ import { describe, expect, jest, test } from '@jest/globals'
 import PDFDocument from 'pdfkit'
 import {
     fitHeadingFontSize,
+    generateInvoicePdf,
     HEADING_MAX_FONT_SIZE,
     HEADING_MIN_FONT_SIZE,
     HEADING_X,
     LOGO_RIGHT_EDGE,
+    type InvoiceData,
 } from '../invoice-generator.ts'
 
 // `import.meta.url` in the font loader cannot be parsed by Jest's CJS transform.
@@ -62,3 +64,57 @@ describe('invoice heading layout', () => {
         expect(fitHeadingFontSize(measure, 'x'.repeat(500), 100)).toBe(HEADING_MIN_FONT_SIZE)
     })
 })
+
+describe('invoice meta block', () => {
+    const BASE: InvoiceData = {
+        invoiceNumber: 'PB-CON26-001',
+        invoiceDate: '01.02.2026',
+        serviceDate: '25.–26.11.2026',
+        purchaserName: 'Erika Musterfrau',
+        purchaserEmail: 'erika@example.de',
+        companyName: null,
+        companyVatId: null,
+        billingAddressLine1: null,
+        billingAddressLine2: null,
+        billingCity: null,
+        billingPostalCode: null,
+        billingCountry: null,
+        conferenceTitle: 'programmier.con 2026',
+        ticketType: 'Regular',
+        ticketCount: 1,
+        unitPriceGrossCents: 11900,
+        subtotalCents: 10000,
+        discountAmountCents: 0,
+        vatAmountCents: 1900,
+        totalGrossCents: 11900,
+    }
+
+    /** Render the PDF and return every string passed to `doc.text`. */
+    async function renderedTexts(data: InvoiceData): Promise<string[]> {
+        const spy = jest.spyOn(PDFDocument.prototype, 'text')
+        try {
+            await generateInvoicePdf(data)
+            return spy.mock.calls.map((call) => String(call[0]))
+        } finally {
+            spy.mockRestore()
+        }
+    }
+
+    test.each([
+        ['invoice', {}],
+        ['correction', { referenceNumber: 'PB-CON26-000', referenceDate: '15.01.2026' }],
+        ['cancellation', { referenceNumber: 'PB-CON26-000', referenceDate: '15.01.2026' }],
+    ] as const)('a %s shows the Leistungsdatum (§ 14 Abs. 4 Nr. 6 UStG)', async (kind, reference) => {
+        const texts = await renderedTexts({ ...BASE, documentKind: kind, ...reference } as InvoiceData)
+
+        expect(texts).toContain('Rechnungsdatum: 01.02.2026')
+        expect(texts).toContain('Leistungsdatum: 25.–26.11.2026')
+    })
+
+    test('omits the Leistungsdatum line when no service date is known', async () => {
+        const texts = await renderedTexts({ ...BASE, serviceDate: null })
+
+        expect(texts.some((text) => text.startsWith('Leistungsdatum'))).toBe(false)
+        expect(texts).toContain('Fälligkeitsdatum: 01.02.2026')
+    })
+})
diff --git a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/__tests__/invoice-service.test.ts b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/__tests__/invoice-service.test.ts
index c6888b33..d95480c7 100644
--- a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/__tests__/invoice-service.test.ts
+++ b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/__tests__/invoice-service.test.ts
@@ -5,6 +5,7 @@ import {
     ensureInvoiceDocuments,
     findCancellationFor,
     findCurrentInvoiceDocument,
+    formatServiceDate,
     InvalidTicketCountError,
     issueOriginalInvoice,
     markInvoiceSent,
@@ -12,14 +13,17 @@ import {
     negateInvoiceSnapshot,
     parseInvoiceSnapshot,
     renderAndUploadInvoice,
+    withServicePeriod,
     type InvoiceDocument,
     type InvoiceOrder,
     type InvoiceSnapshot,
     type RenderInvoiceParams,
 } from '../invoice-service.ts'
+import { postSlackMessage } from '../postSlackMessage.ts'
 
 // `import.meta.url` in the font loader cannot be parsed by Jest's CJS transform.
 jest.mock('../museo-font.ts', () => ({ tryLoadMuseoFont: () => null }))
+jest.mock('../postSlackMessage.ts', () => ({ postSlackMessage: jest.fn(async () => undefined) }))
 
 const ORDER: InvoiceOrder & { order_number: string } = {
     id: 'order-1',
@@ -159,6 +163,67 @@ describe('buildInvoiceSnapshot', () => {
     })
 })
 
+describe('Leistungsdatum (service date)', () => {
+    const CONFERENCE = { start_on: '2026-11-25T09:00:00', end_on: '2026-11-26T18:00:00' }
+
+    test.each([
+        ['2026-11-25', '2026-11-26', '25.–26.11.2026'],
+        ['2026-11-25T09:00:00', '2026-11-25T18:00:00', '25.11.2026'],
+        ['2026-11-25', null, '25.11.2026'],
+        ['2026-11-30', '2026-12-01', '30.11.–01.12.2026'],
+        ['2026-12-31', '2027-01-01', '31.12.2026–01.01.2027'],
+        [null, null, null],
+    ])('formats %s / %s as %s', (start, end, expected) => {
+        expect(formatServiceDate(start, end)).toBe(expected)
+    })
+
+    test('buildInvoiceSnapshot records the conference dates', () => {
+        const snapshot = buildInvoiceSnapshot(ORDER, 'Conf', 2, CONFERENCE)
+        expect(snapshot.service_date_start).toBe('2026-11-25')
+        expect(snapshot.service_date_end).toBe('2026-11-26')
+    })
+
+    test('withServicePeriod fills older snapshots and keeps recorded dates', () => {
+        const legacy = buildInvoiceSnapshot(ORDER, 'Conf', 2)
+        expect(withServicePeriod(legacy, CONFERENCE)).toMatchObject({
+            service_date_start: '2026-11-25',
+            service_date_end: '2026-11-26',
+        })
+
+        const recorded = buildInvoiceSnapshot(ORDER, 'Conf', 2, { start_on: '2025-11-20', end_on: '2025-11-21' })
+        expect(withServicePeriod(recorded, CONFERENCE)).toBe(recorded)
+    })
+
+    test('renders without a Leistungsdatum and alerts Slack when no date is known', async () => {
+        const postSlackMessageMock = jest.mocked(postSlackMessage)
+        postSlackMessageMock.mockClear()
+        const logger = { warn: jest.fn() }
+        const result = await renderAndUploadInvoice({
+            snapshot: buildInvoiceSnapshot(ORDER, 'Conf', 2),
+            invoiceNumber: 'PB-CON26-001',
+            invoiceDate: new Date('2026-02-01T10:00:00Z'),
+            filesService: fakeFilesService(),
+            logger,
+        })
+        expect(result.pdfBuffer.subarray(0, 4).toString()).toBe('%PDF')
+        expect(logger.warn).toHaveBeenCalledWith(expect.stringMatching(/PB-CON26-001 has no Leistungsdatum/))
+        expect(postSlackMessageMock).toHaveBeenCalledTimes(1)
+        expect(postSlackMessageMock.mock.calls[0]![0]).toMatch(/Invoice document PB-CON26-001 has no Leistungsdatum/)
+    })
+
+    test('does not alert Slack when the snapshot carries the conference dates', async () => {
+        const postSlackMessageMock = jest.mocked(postSlackMessage)
+        postSlackMessageMock.mockClear()
+        await renderAndUploadInvoice({
+            snapshot: buildInvoiceSnapshot(ORDER, 'Conf', 2, CONFERENCE),
+            invoiceNumber: 'PB-CON26-001',
+            invoiceDate: new Date('2026-02-01T10:00:00Z'),
+            filesService: fakeFilesService(),
+        })
+        expect(postSlackMessageMock).not.toHaveBeenCalled()
+    })
+})
+
 describe('negateInvoiceSnapshot', () => {
     test('flips every monetary amount and keeps the rest', () => {
         const snapshot = buildInvoiceSnapshot(ORDER, 'Conf', 2)
diff --git a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/__tests__/secure-invoice-folder.test.ts b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/__tests__/secure-invoice-folder.test.ts
index 22ef64d7..4399c618 100644
--- a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/__tests__/secure-invoice-folder.test.ts
+++ b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/__tests__/secure-invoice-folder.test.ts
@@ -80,6 +80,8 @@ const SNAPSHOT = {
     billing_postal_code: '61231',
     billing_country: 'Deutschland',
     conference_title: 'programmier.con 2026',
+    service_date_start: '2026-11-25',
+    service_date_end: '2026-11-26',
     ticket_type: 'regular',
     ticket_count: 1,
     unit_price_gross_cents: 11900,
diff --git a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/invoice-generator.ts b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/invoice-generator.ts
index 6c97e0ed..7aadbabb 100644
--- a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/invoice-generator.ts
+++ b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/invoice-generator.ts
@@ -61,6 +61,11 @@ export type InvoiceDocumentKind = 'invoice' | 'correction' | 'cancellation'
 interface InvoiceDataBase {
     invoiceNumber: string
     invoiceDate: string // formatted DD.MM.YYYY
+    /**
+     * Leistungsdatum (§ 14 Abs. 4 Nr. 6 UStG): the conference date(s), e.g.
+     * "25.–26.11.2026". The line is omitted when no date is known.
+     */
+    serviceDate?: string | null
     // Customer
     purchaserName: string
     purchaserEmail: string
@@ -228,18 +233,24 @@ export function generateInvoicePdf(data: InvoiceData): Promise<Buffer> {
         const metaY = headingWrapped ? Math.ceil(50 + headingHeight + 6) : 75
 
         doc.fontSize(9).fillColor('#666')
-        doc.text(`Rechnungsdatum: ${data.invoiceDate}`, 50, metaY, { align: 'right' })
+        let metaLineY = metaY
+        const metaLine = (text: string) => {
+            doc.text(text, 50, metaLineY, { align: 'right' })
+            metaLineY += 12
+        }
+        metaLine(`Rechnungsdatum: ${data.invoiceDate}`)
+        if (data.serviceDate) {
+            metaLine(`Leistungsdatum: ${data.serviceDate}`)
+        }
         if (kind === 'invoice') {
-            doc.text(`Fälligkeitsdatum: ${data.invoiceDate}`, 50, metaY + 12, { align: 'right' })
+            metaLine(`Fälligkeitsdatum: ${data.invoiceDate}`)
         } else {
             // referenceNumber/referenceDate are guaranteed by the guard above.
-            doc.text(`Bezug: Rechnung Nr. ${data.referenceNumber} vom ${data.referenceDate}`, 50, metaY + 12, {
-                align: 'right',
-            })
+            metaLine(`Bezug: Rechnung Nr. ${data.referenceNumber} vom ${data.referenceDate}`)
         }
 
         // --- Seller info ---
-        let y = Math.max(115, metaY + 40)
+        let y = Math.max(115, metaLineY + 16)
         doc.fontSize(9).fillColor('#333')
         doc.text(SELLER.name, 50, y)
         y += 13
diff --git a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/invoice-service.ts b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/invoice-service.ts
index 63a1ed86..f212472f 100644
--- a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/invoice-service.ts
+++ b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/shared/invoice-service.ts
@@ -1,5 +1,6 @@
 import { Readable } from 'node:stream'
 import { generateInvoicePdf, ticketTypeLabel, type InvoiceData, type InvoiceDocumentKind } from './invoice-generator.js'
+import { postSlackMessage } from './postSlackMessage.js'
 import { uploadWithInvoiceFolderFallback } from './secure-invoice-folder.js'
 
 /** Order fields required to assemble an invoice (subset of `ticket_orders`). */
@@ -24,6 +25,12 @@ export interface InvoiceOrder {
     ticket_type: string
 }
 
+/** Conference dates the Leistungsdatum is derived from (subset of `conferences`). */
+export interface ServicePeriod {
+    start_on?: string | null
+    end_on?: string | null
+}
+
 /** Document types stored in `ticket_invoices.type`. */
 export type InvoiceDocumentType = 'original' | 'correction' | 'cancellation'
 
@@ -45,6 +52,12 @@ export interface InvoiceSnapshot {
     billing_postal_code: string | null
     billing_country: string | null
     conference_title: string
+    /**
+     * Leistungsdatum (§ 14 Abs. 4 Nr. 6 UStG): first/last conference day as
+     * YYYY-MM-DD. Absent on snapshots written before the field was introduced.
+     */
+    service_date_start?: string | null
+    service_date_end?: string | null
     ticket_type: string
     ticket_count: number
     unit_price_gross_cents: number
@@ -75,6 +88,52 @@ export function formatInvoiceDate(date: Date): string {
     })
 }
 
+/** The YYYY-MM-DD part of a Directus date/dateTime value, or null. */
+function toIsoDate(value: string | null | undefined): string | null {
+    const match = typeof value === 'string' ? /^\d{4}-\d{2}-\d{2}/.exec(value) : null
+    return match ? match[0] : null
+}
+
+/**
+ * Format the Leistungsdatum in German notation: "25.11.2026" for a single day,
+ * "25.–26.11.2026" for a range within one month, otherwise both full dates
+ * (shortened where the year is shared). Returns null when no date is known.
+ */
+export function formatServiceDate(start: string | null | undefined, end: string | null | undefined): string | null {
+    const from = toIsoDate(start) ?? toIsoDate(end)
+    if (!from) {
+        return null
+    }
+    const to = toIsoDate(end)
+    const [fromYear, fromMonth, fromDay] = from.split('-')
+    if (!to || to <= from) {
+        return `${fromDay}.${fromMonth}.${fromYear}`
+    }
+    const [toYear, toMonth, toDay] = to.split('-')
+    if (fromYear !== toYear) {
+        return `${fromDay}.${fromMonth}.${fromYear}–${toDay}.${toMonth}.${toYear}`
+    }
+    if (fromMonth !== toMonth) {
+        return `${fromDay}.${fromMonth}.–${toDay}.${toMonth}.${toYear}`
+    }
+    return `${fromDay}.–${toDay}.${toMonth}.${toYear}`
+}
+
+/**
+ * Fill in the conference dates on a snapshot written before the Leistungsdatum
+ * was recorded. Snapshots that already carry a date are returned unchanged.
+ */
+export function withServicePeriod(snapshot: InvoiceSnapshot, servicePeriod?: ServicePeriod): InvoiceSnapshot {
+    if (snapshot.service_date_start || snapshot.service_date_end) {
+        return snapshot
+    }
+    return {
+        ...snapshot,
+        service_date_start: toIsoDate(servicePeriod?.start_on),
+        service_date_end: toIsoDate(servicePeriod?.end_on),
+    }
+}
+
 /**
  * Thrown by {@link buildInvoiceSnapshot} when the ticket count is not a positive
  * number. Dividing by 0 (or NaN) would silently bake Infinity/NaN amounts into the
@@ -100,7 +159,8 @@ export class InvalidTicketCountError extends Error {
 export function buildInvoiceSnapshot(
     order: InvoiceOrder,
     conferenceTitle: string,
-    ticketCount: number
+    ticketCount: number,
+    servicePeriod?: ServicePeriod
 ): InvoiceSnapshot {
     if (!Number.isFinite(ticketCount) || ticketCount <= 0) {
         throw new InvalidTicketCountError(order.order_number, ticketCount)
@@ -127,6 +187,8 @@ export function buildInvoiceSnapshot(
         billing_postal_code: order.billing_postal_code,
         billing_country: order.billing_country,
         conference_title: conferenceTitle,
+        service_date_start: toIsoDate(servicePeriod?.start_on),
+        service_date_end: toIsoDate(servicePeriod?.end_on),
         ticket_type: order.ticket_type,
         ticket_count: ticketCount,
         unit_price_gross_cents: grossPerTicket,
@@ -217,9 +279,21 @@ export async function renderAndUploadInvoice(params: RenderInvoiceParams): Promi
     const { snapshot, invoiceNumber, invoiceDate, filesService } = params
     const kind: InvoiceDocumentKind = params.documentKind || 'invoice'
 
+    const serviceDate = formatServiceDate(snapshot.service_date_start, snapshot.service_date_end)
+    if (!serviceDate) {
+        // Non-blocking like the invoice folder fallback, but the document lacks a
+        // mandatory field (§ 14 Abs. 4 Nr. 6 UStG), so a human has to follow up.
+        const message = `Invoice document ${invoiceNumber} has no Leistungsdatum because its conference has no start_on/end_on. Set the conference dates; if the document has already been sent, issue a Rechnungsberichtigung.`
+        params.logger?.warn(message)
+        postSlackMessage(`:rotating_light: *Invoices*: ${message}`).catch((error: any) => {
+            params.logger?.warn(`Could not send Slack alert for ${invoiceNumber}: ${error?.message ?? error}`)
+        })
+    }
+
     const baseData = {
         invoiceNumber,
         invoiceDate: formatInvoiceDate(invoiceDate),
+        serviceDate,
         purchaserName: snapshot.purchaser_name,
         purchaserEmail: snapshot.purchaser_email,
         companyName: snapshot.company_name,
@@ -279,6 +353,7 @@ export async function renderAndUploadInvoice(params: RenderInvoiceParams): Promi
 export interface IssueOriginalInvoiceParams {
     order: InvoiceOrder
     conferenceTitle: string
+    servicePeriod?: ServicePeriod
     ticketCount: number
     invoiceNumber: string
     invoiceDate: Date
@@ -304,7 +379,7 @@ export interface IssueOriginalInvoiceResult extends RenderInvoiceResult {
 export async function issueOriginalInvoice(params: IssueOriginalInvoiceParams): Promise<IssueOriginalInvoiceResult> {
     const { order, conferenceTitle, ticketCount, invoiceNumber, invoiceDate, ordersService, invoicesService } = params
 
-    const snapshot = buildInvoiceSnapshot(order, conferenceTitle, ticketCount)
+    const snapshot = buildInvoiceSnapshot(order, conferenceTitle, ticketCount, params.servicePeriod)
 
     const rendered = await renderAndUploadInvoice({
         snapshot,
@@ -411,6 +486,7 @@ export class MissingDatePaidError extends Error {
 export interface EnsureInvoiceDocumentParams {
     order: InvoiceOrder & { invoice_number?: string | null; invoice_file?: string | null; date_paid?: string | null }
     conferenceTitle: string
+    servicePeriod?: ServicePeriod
     ticketCount: number
     invoicesService: any
 }
@@ -443,7 +519,7 @@ export async function ensureInvoiceDocuments(params: EnsureInvoiceDocumentParams
     }
 
     const issuedAt = new Date(order.date_paid)
-    const snapshot = buildInvoiceSnapshot(order, params.conferenceTitle, params.ticketCount)
+    const snapshot = buildInvoiceSnapshot(order, params.conferenceTitle, params.ticketCount, params.servicePeriod)
 
     await invoicesService.createOne({
         order: order.id,
diff --git a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/ticket-order-processing/__tests__/index.test.ts b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/ticket-order-processing/__tests__/index.test.ts
index 4512ee05..c1e35702 100644
--- a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/ticket-order-processing/__tests__/index.test.ts
+++ b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/ticket-order-processing/__tests__/index.test.ts
@@ -75,7 +75,13 @@ const ORDER = {
     is_internal: false,
 }
 
-const CONFERENCE = { id: 'conf-1', title: 'programmier.con 2026', start_on: '2026-03-01', ticket_max_quantity: null }
+const CONFERENCE = {
+    id: 'conf-1',
+    title: 'programmier.con 2026',
+    start_on: '2026-03-01',
+    end_on: '2026-03-02',
+    ticket_max_quantity: null,
+}
 
 function setup(orderOverrides: Record<string, any> = {}) {
     const order = { ...ORDER, ...orderOverrides }
@@ -163,6 +169,8 @@ describe('ticket-order-processing hook', () => {
         const issueParams = issueOriginalInvoiceMock.mock.calls[0]![0]
         expect(issueParams.invoiceNumber).toBe('PB-CON26-001')
         expect(issueParams.ticketCount).toBe(2)
+        // The conference dates become the invoice's Leistungsdatum.
+        expect(issueParams.servicePeriod).toEqual({ start_on: '2026-03-01', end_on: '2026-03-02' })
         expect(issueParams.invoicesService).toBe(serviceInstances['ticket_invoices']![0])
 
         // The confirmation email carries the invoice PDF.
diff --git a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/ticket-order-processing/index.ts b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/ticket-order-processing/index.ts
index 0dca5107..96871c84 100644
--- a/directus-cms/extensions/directus-extension-programmierbar-bundle/src/ticket-order-processing/index.ts
+++ b/directus-cms/extensions/directus-extension-programmierbar-bundle/src/ticket-order-processing/index.ts
@@ -112,9 +112,10 @@ export default defineHook(({ action }, hookContext) => {
                         continue
                     }
 
-                    // Get conference details (title + start_on for invoice year + ticket limit)
+                    // Get conference details (title, start_on for invoice year, start_on/end_on
+                    // for the Leistungsdatum, ticket limit)
                     const conference = await conferencesService.readOne(order.conference, {
-                        fields: ['title', 'start_on', 'ticket_max_quantity'],
+                        fields: ['title', 'start_on', 'end_on', 'ticket_max_quantity'],
                     })
 
                     if (!conference) {
@@ -199,6 +200,7 @@ export default defineHook(({ action }, hookContext) => {
                         const invoiceResult = await issueOriginalInvoice({
                             order,
                             conferenceTitle: conference.title,
+                            servicePeriod: { start_on: conference.start_on, end_on: conference.end_on },
                             ticketCount: attendees.length,
                             invoiceNumber,
                             invoiceDate: new Date(),