diff --git a/.github/workflows/gh-pages.yaml b/.github/workflows/gh-pages.yaml
index dec45682e..81fa15cb4 100644
--- a/.github/workflows/gh-pages.yaml
+++ b/.github/workflows/gh-pages.yaml
@@ -25,17 +25,17 @@ jobs:
 
     steps:
       - name: Checkout 🛎️
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: pnpm 🧰
-        uses: pnpm/action-setup@v3
+        uses: pnpm/action-setup@v6
         with:
           version: 8
 
       - name: Node 🧰
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@v7
         with:
-          node-version: "latest"
+          node-version: 22.x
           cache: "pnpm"
 
       - name: Install 📦
@@ -45,10 +45,10 @@ jobs:
         run: pnpm docs:build
 
       - name: Setup Pages 🧰
-        uses: actions/configure-pages@v4
+        uses: actions/configure-pages@v6
 
       - name: Upload artifact 🚀
-        uses: actions/upload-pages-artifact@v3
+        uses: actions/upload-pages-artifact@v5
         with:
           path: ./packages/docs/dist/
 
@@ -64,4 +64,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages 🚀
         id: deployment
-        uses: actions/deploy-pages@v4
+        uses: actions/deploy-pages@v5
diff --git a/.github/workflows/pgk-pr-new.yaml b/.github/workflows/pgk-pr-new.yaml
index 42cd12f73..df820f898 100644
--- a/.github/workflows/pgk-pr-new.yaml
+++ b/.github/workflows/pgk-pr-new.yaml
@@ -19,15 +19,15 @@ jobs:
 
     steps:
       - name: Checkout 🛎️
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
         with:
           persist-credentials: false
 
       - name: pnpm 🧰
-        uses: pnpm/action-setup@v4
+        uses: pnpm/action-setup@v6
 
       - name: Node 🧰
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v7
         with:
           node-version: 22.x
 
diff --git a/.github/workflows/publish.yaml b/.github/workflows/publish.yaml
index 266f206cb..bac611c2b 100644
--- a/.github/workflows/publish.yaml
+++ b/.github/workflows/publish.yaml
@@ -14,19 +14,21 @@ jobs:
 
     steps:
       - name: Checkout 🛎️
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: pnpm 🧰
-        uses: pnpm/action-setup@v4
+        uses: pnpm/action-setup@v6
 
       - name: Node 🧰
-        uses: actions/setup-node@v5
+        uses: actions/setup-node@v7
         with:
-          node-version: 20.x
+          node-version: 22.x
           registry-url: https://registry.npmjs.org
           cache: 'pnpm'
 
       - name: Update npm
+        # Keep this in step with node-version above: npm 12 requires Node >=22.22.2, so on the
+        # previous 20.x runner `npm@latest` failed with EBADENGINE.
         run: npm install -g npm@latest
 
       - name: Install 📦
diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
index 077a5670f..56eb7a449 100644
--- a/.github/workflows/release.yaml
+++ b/.github/workflows/release.yaml
@@ -10,10 +10,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout 🛎️
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Create a draft GitHub release 🎁
-        uses: softprops/action-gh-release@v1
+        uses: softprops/action-gh-release@v3
         with:
           token: ${{ secrets.COMMERCELAYER_CI_TOKEN }}
           draft: true
diff --git a/lerna.json b/lerna.json
index e8678aaab..7fb960290 100644
--- a/lerna.json
+++ b/lerna.json
@@ -2,7 +2,7 @@
   "$schema": "node_modules/lerna/schemas/lerna-schema.json",
   "useNx": false,
   "npmClient": "pnpm",
-  "version": "4.29.7",
+  "version": "4.29.8-beta.0",
   "command": {
     "version": {
       "preid": "beta"
diff --git a/packages/react-components/package.json b/packages/react-components/package.json
index 844bf7e79..8710c4ffc 100644
--- a/packages/react-components/package.json
+++ b/packages/react-components/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@commercelayer/react-components",
-  "version": "4.29.7",
+  "version": "4.29.8-beta.0",
   "description": "The Official Commerce Layer React Components",
   "main": "lib/cjs/index.js",
   "module": "lib/esm/index.js",
diff --git a/packages/react-components/specs/payment_source/AdyenPayment.shopperLocale.spec.tsx b/packages/react-components/specs/payment_source/AdyenPayment.shopperLocale.spec.tsx
new file mode 100644
index 000000000..6f2aea1fb
--- /dev/null
+++ b/packages/react-components/specs/payment_source/AdyenPayment.shopperLocale.spec.tsx
@@ -0,0 +1,206 @@
+// The Drop-in was translated correctly but the Klarna page it redirects to came up in Italian.
+// `locale` in the Core configuration is client-side only — it picks the Drop-in's translation
+// bundle and never reaches Adyen. The language Adyen uses for the hosted pages it renders
+// itself comes from `shopperLocale` in the payment request, which was not being sent.
+import { act, render } from "@testing-library/react"
+import { AdyenPayment } from "#components/payment_source/AdyenPayment"
+import CommerceLayerContext from "#context/CommerceLayerContext"
+import CustomerContext from "#context/CustomerContext"
+import OrderContext, { defaultOrderContext } from "#context/OrderContext"
+import PaymentMethodContext, {
+  defaultPaymentMethodContext,
+} from "#context/PaymentMethodContext"
+import PlaceOrderContext, {
+  defaultPlaceOrderContext,
+} from "#context/PlaceOrderContext"
+
+const adyen = vi.hoisted(() => ({
+  // biome-ignore lint/suspicious/noExplicitAny: test cast
+  captured: { options: null as any },
+}))
+
+vi.mock("@adyen/adyen-web/auto", () => ({
+  // biome-ignore lint/suspicious/noExplicitAny: test cast
+  AdyenCheckout: vi.fn(async (options: any) => {
+    adyen.captured.options = options
+    return { update: vi.fn() }
+  }),
+  Dropin: class FakeDropin {
+    mount(): this {
+      return this
+    }
+    submit(): void {}
+    remove(): void {}
+    unmount(): this {
+      return this
+    }
+    handleAction(): void {}
+  },
+}))
+
+vi.mock("#utils/getPublicIp", () => ({
+  getPublicIP: vi.fn(async () => "127.0.0.1"),
+}))
+
+const PAYMENT_SOURCE = {
+  id: "ps-1",
+  type: "adyen_payments",
+  payment_methods: {
+    paymentMethods: [{ type: "scheme" }, { type: "klarna_account" }],
+  },
+}
+
+/**
+ * Mounts the component for an order in `languageCode`, submits a card, and returns the
+ * `payment_request_data` that went to the API.
+ */
+async function submitAndCapturePaymentRequest({
+  languageCode,
+  shopperLocaleConfig,
+}: {
+  languageCode?: string
+  shopperLocaleConfig?: string
+  // biome-ignore lint/suspicious/noExplicitAny: test cast
+}): Promise<{ paymentRequestData: any; dropInLocale: string }> {
+  const setPaymentSource = vi.fn(async () => ({
+    ...PAYMENT_SOURCE,
+    payment_response: {},
+  }))
+  // biome-ignore lint/suspicious/noExplicitAny: test cast
+  const order: any = {
+    id: "order-1",
+    status: "pending",
+    payment_status: "unpaid",
+    currency_code: "EUR",
+    country_code: "IT",
+    language_code: languageCode,
+    total_amount_with_taxes_cents: 1000,
+    line_items: [],
+  }
+
+  await act(async () => {
+    render(
+      <CommerceLayerContext.Provider value={{ accessToken: "test-token" }}>
+        <OrderContext.Provider
+          value={{
+            ...defaultOrderContext,
+            orderId: order.id,
+            order,
+            updateOrder: vi.fn(),
+            getOrderByFields: vi.fn().mockResolvedValue({
+              status: "pending",
+              payment_status: "unpaid",
+            }),
+          }}
+        >
+          <CustomerContext.Provider value={{}}>
+            <PlaceOrderContext.Provider value={defaultPlaceOrderContext}>
+              <PaymentMethodContext.Provider
+                value={
+                  {
+                    ...defaultPaymentMethodContext,
+                    _isProvided: true as const,
+                    paymentSource: PAYMENT_SOURCE,
+                    currentPaymentMethodType: "scheme",
+                    setPaymentSource,
+                    setPaymentMethodErrors: vi.fn(),
+                    setPaymentRef: vi.fn(),
+                    errors: [],
+                    // biome-ignore lint/suspicious/noExplicitAny: test cast
+                  } as any
+                }
+              >
+                <AdyenPayment
+                  clientKey="test_CLIENTKEY"
+                  config={
+                    shopperLocaleConfig
+                      ? { shopperLocale: shopperLocaleConfig }
+                      : {}
+                  }
+                />
+              </PaymentMethodContext.Provider>
+            </PlaceOrderContext.Provider>
+          </CustomerContext.Provider>
+        </OrderContext.Provider>
+      </CommerceLayerContext.Provider>,
+    )
+  })
+  await act(async () => {
+    await new Promise((resolve) => setTimeout(resolve, 0))
+  })
+
+  await act(async () => {
+    adyen.captured.options.onSubmit(
+      { data: { paymentMethod: { type: "scheme" } }, isValid: true },
+      { mount: vi.fn() },
+      { resolve: vi.fn(), reject: vi.fn() },
+    )
+    await new Promise((resolve) => setTimeout(resolve, 0))
+  })
+
+  const call = setPaymentSource.mock.calls
+    // biome-ignore lint/suspicious/noExplicitAny: test cast
+    .map(([args]: any[]) => args)
+    // biome-ignore lint/suspicious/noExplicitAny: test cast
+    .find((args: any) => args?.attributes?.payment_request_data != null)
+  return {
+    paymentRequestData: call?.attributes?.payment_request_data,
+    dropInLocale: adyen.captured.options.locale,
+  }
+}
+
+describe("AdyenPayment shopperLocale", () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    adyen.captured.options = null
+  })
+
+  it("sends shopperLocale derived from the order language", async () => {
+    const { paymentRequestData, dropInLocale } =
+      await submitAndCapturePaymentRequest({
+        languageCode: "en",
+      })
+
+    // The Drop-in keeps the bare language it always used — this is only about what Adyen gets.
+    expect(dropInLocale).toBe("en")
+    expect(paymentRequestData.shopperLocale).toBe("en-US")
+  })
+
+  it("does not take the language from the country code", async () => {
+    // The bug: an English order in an Italian market rendered a Klarna page in Italian, because
+    // nothing carried the language and Adyen fell back to the country.
+    const { paymentRequestData } = await submitAndCapturePaymentRequest({
+      languageCode: "en",
+    })
+
+    expect(paymentRequestData.shopperLocale).not.toContain("it")
+  })
+
+  it("lets the config override the derived value", async () => {
+    const { paymentRequestData } = await submitAndCapturePaymentRequest({
+      languageCode: "en",
+      shopperLocaleConfig: "en-GB",
+    })
+
+    expect(paymentRequestData.shopperLocale).toBe("en-GB")
+  })
+
+  it("omits shopperLocale when the language cannot be expanded", async () => {
+    const { paymentRequestData } = await submitAndCapturePaymentRequest({
+      languageCode: "xx",
+    })
+
+    // Preserves Adyen's existing fallback rather than sending something it may reject.
+    expect(paymentRequestData).not.toHaveProperty("shopperLocale")
+  })
+
+  it("falls back to the locale prop when the order has no language", async () => {
+    const { paymentRequestData, dropInLocale } = await submitAndCapturePaymentRequest({
+      languageCode: undefined,
+    })
+
+    // Same source the Drop-in falls back to, so the two stay consistent.
+    expect(dropInLocale).toBe("en_US")
+    expect(paymentRequestData.shopperLocale).toBe("en-US")
+  })
+})
diff --git a/packages/react-components/specs/utils/adyenShopperLocale.spec.ts b/packages/react-components/specs/utils/adyenShopperLocale.spec.ts
new file mode 100644
index 000000000..5ffb31c20
--- /dev/null
+++ b/packages/react-components/specs/utils/adyenShopperLocale.spec.ts
@@ -0,0 +1,36 @@
+// Adyen's `locale` (Drop-in translations, client-side) and `shopperLocale` (payment request,
+// used for the hosted pages Adyen renders itself) are different things. Commerce Layer's
+// `order.language_code` is a bare ISO 639-1 code, so it has to be expanded for the latter.
+import { getAdyenShopperLocale } from "#utils/adyenShopperLocale"
+
+describe("getAdyenShopperLocale", () => {
+  it("expands a bare language whose region mirrors it", () => {
+    expect(getAdyenShopperLocale("it")).toBe("it-IT")
+    expect(getAdyenShopperLocale("de")).toBe("de-DE")
+    expect(getAdyenShopperLocale("fr")).toBe("fr-FR")
+    expect(getAdyenShopperLocale("nl")).toBe("nl-NL")
+  })
+
+  it("expands a bare language whose region differs", () => {
+    // The reported case: an English Drop-in handing over to a Klarna page. `en-EN` is not a
+    // locale, so it needs the explicit mapping.
+    expect(getAdyenShopperLocale("en")).toBe("en-US")
+    expect(getAdyenShopperLocale("sv")).toBe("sv-SE")
+    expect(getAdyenShopperLocale("cs")).toBe("cs-CZ")
+    expect(getAdyenShopperLocale("ja")).toBe("ja-JP")
+  })
+
+  it("normalises a locale that already carries a region", () => {
+    expect(getAdyenShopperLocale("en-US")).toBe("en-US")
+    expect(getAdyenShopperLocale("en_US")).toBe("en-US")
+    expect(getAdyenShopperLocale("PT_br")).toBe("pt-BR")
+  })
+
+  it("returns undefined rather than guessing", () => {
+    // Preserves Adyen's own fallback instead of sending a locale it may reject.
+    expect(getAdyenShopperLocale(undefined)).toBeUndefined()
+    expect(getAdyenShopperLocale(null)).toBeUndefined()
+    expect(getAdyenShopperLocale("")).toBeUndefined()
+    expect(getAdyenShopperLocale("xx")).toBeUndefined()
+  })
+})
diff --git a/packages/react-components/src/components/payment_source/AdyenPayment.tsx b/packages/react-components/src/components/payment_source/AdyenPayment.tsx
index 55473ce5d..074fc92bf 100644
--- a/packages/react-components/src/components/payment_source/AdyenPayment.tsx
+++ b/packages/react-components/src/components/payment_source/AdyenPayment.tsx
@@ -32,6 +32,7 @@ import CustomerContext from "#context/CustomerContext"
 import OrderContext from "#context/OrderContext"
 import PaymentMethodContext from "#context/PaymentMethodContext"
 import PlaceOrderContext from "#context/PlaceOrderContext"
+import { getAdyenShopperLocale } from "#utils/adyenShopperLocale"
 import browserInfo, { cleanUrlBy } from "#utils/browserInfo"
 import { getPublicIP } from "#utils/getPublicIp"
 import { hasSubscriptions } from "#utils/hasSubscriptions"
@@ -111,6 +112,20 @@ export interface AdyenPaymentConfig {
    */
   onSelect?: (component: UIElement<UIElementProps>) => void
   giftcardErrorComponent?: (message: string) => JSX.Element
+  /**
+   * The locale Adyen should use for anything **it** renders — in particular the hosted page a
+   * redirect payment method sends the shopper to (Klarna, iDEAL, …). Sent as `shopperLocale`
+   * in the payment request.
+   *
+   * This is not the same as the Drop-in's `locale`, which only selects the client-side
+   * translation bundle. Without a `shopperLocale` Adyen falls back to the merchant account
+   * default or the country code, so a Drop-in in English can hand over to a Klarna page in
+   * Italian.
+   *
+   * @default derived from `order.language_code` (see `getAdyenShopperLocale`)
+   * @example "en-US"
+   */
+  shopperLocale?: string
 }
 
 interface Props {
@@ -138,6 +153,7 @@ export function AdyenPayment({
     onReady,
     onSelect,
     subscriptionPaymentMethods,
+    shopperLocale: shopperLocaleConfig,
   } = {
     ...defaultConfig,
     ...config,
@@ -162,6 +178,13 @@ export function AdyenPayment({
   const { customers } = useContext(CustomerContext)
   const ref = useRef<null | HTMLFormElement>(null)
   const dropinRef = useRef<Dropin | null>(null)
+  // Two distinct locales, deliberately derived from the same source (see the Core `options`
+  // below, which uses the first one): `dropInLocale` only selects the Drop-in's client-side
+  // translations, while `shopperLocale` travels with the payment request and is what Adyen
+  // uses for the hosted pages it renders itself.
+  const dropInLocale = order?.language_code ?? locale
+  const shopperLocale =
+    shopperLocaleConfig ?? getAdyenShopperLocale(dropInLocale)
   const handleSubmit = async (
     e: FormEvent<HTMLFormElement>,
   ): Promise<boolean> => {
@@ -297,6 +320,11 @@ export function AdyenPayment({
         redirect_from_issuer_method: "GET",
         shopper_ip: shopperIp,
         shopperInteraction: "Ecommerce",
+        // The language Adyen renders its own hosted pages in (the Klarna screen a redirect
+        // method hands over to). The Drop-in's `locale` is client-side only and never reaches
+        // Adyen, so without this the hosted page falls back to the account default or the
+        // country code.
+        ...(shopperLocale != null ? { shopperLocale } : {}),
         browser_info: {
           ...browserInfo(),
         },
@@ -536,7 +564,7 @@ export function AdyenPayment({
           : paymentMethodsResponse.paymentMethods
     }
     const options = {
-      locale: order?.language_code ?? locale,
+      locale: dropInLocale,
       environment,
       clientKey,
       amount: {
diff --git a/packages/react-components/src/utils/adyenShopperLocale.ts b/packages/react-components/src/utils/adyenShopperLocale.ts
new file mode 100644
index 000000000..a9ce74e31
--- /dev/null
+++ b/packages/react-components/src/utils/adyenShopperLocale.ts
@@ -0,0 +1,84 @@
+/**
+ * Adyen uses two different locales, and they are not interchangeable:
+ *
+ * - `locale` in the Core configuration is **client-side only** — it picks the Drop-in's
+ *   translation bundle.
+ * - `shopperLocale` in the payment request is what Adyen uses for anything it renders
+ *   itself, in particular the hosted pages a redirect payment method sends the shopper to
+ *   (Klarna, iDEAL, …). Without it Adyen falls back to the merchant account default or the
+ *   country code, which is why a Drop-in in English could hand over to a Klarna page in
+ *   Italian.
+ *
+ * Adyen expects a language code combined with a region (`en-US`, `it-IT`). Commerce Layer's
+ * `order.language_code` is a bare ISO 639-1 code (`en`, `it`), so it has to be expanded.
+ */
+
+/**
+ * Region to pair with a bare language code. Only languages whose Adyen-supported locale
+ * cannot be derived by uppercasing the language itself need an entry here.
+ */
+const REGION_BY_LANGUAGE: Record<string, string> = {
+  en: "US",
+  zh: "CN",
+  ar: "AE",
+  he: "IL",
+  ja: "JP",
+  ko: "KR",
+  uk: "UA",
+  el: "GR",
+  cs: "CZ",
+  da: "DK",
+  sv: "SE",
+  nb: "NO",
+  no: "NO",
+  sl: "SI",
+  et: "EE",
+  be: "BY",
+}
+
+/** Languages for which `xx` → `xx-XX` is the Adyen-supported locale (it → it-IT, and so on). */
+const SELF_REGION_LANGUAGES = new Set([
+  "it",
+  "de",
+  "fr",
+  "es",
+  "pt",
+  "nl",
+  "pl",
+  "fi",
+  "hu",
+  "ro",
+  "ru",
+  "sk",
+  "tr",
+  "hr",
+  "lt",
+  "lv",
+  "bg",
+  "is",
+])
+
+/**
+ * Resolves the `shopperLocale` to send with an Adyen payment request.
+ *
+ * @param locale the locale already driving the Drop-in — `order.language_code`, or the
+ *   component's `locale` prop. Accepts a bare language (`en`), or a language and region in
+ *   either separator (`en-US`, `en_US`).
+ * @returns an Adyen-style `language-REGION` locale, or `undefined` when the language cannot
+ *   be expanded confidently. Returning `undefined` deliberately preserves Adyen's own
+ *   fallback rather than sending a locale it may reject.
+ */
+export function getAdyenShopperLocale(
+  locale?: string | null,
+): string | undefined {
+  if (locale == null) return undefined
+  const [rawLanguage, rawRegion] = locale.replace("_", "-").split("-")
+  const language = rawLanguage?.toLowerCase()
+  if (!language) return undefined
+  // Already carries a region: normalise the separator and casing and trust it.
+  if (rawRegion) return `${language}-${rawRegion.toUpperCase()}`
+  const region =
+    REGION_BY_LANGUAGE[language] ??
+    (SELF_REGION_LANGUAGES.has(language) ? language.toUpperCase() : undefined)
+  return region ? `${language}-${region}` : undefined
+}