diff --git a/integration_test_utils.py b/integration_test_utils.py
index dd245ef..78af49c 100644
--- a/integration_test_utils.py
+++ b/integration_test_utils.py
@@ -45,12 +45,17 @@
 from ucp_sdk.models.schemas.shopping.types import (
   fulfillment_method_create_request,
 )
+from ucp_sdk.models.schemas.shopping.types.amount import Amount
 from ucp_sdk.models.schemas.shopping.types import item_create_request
 from ucp_sdk.models.schemas.shopping.types import item_update_request
 from ucp_sdk.models.schemas.shopping.types import line_item_create_request
 from ucp_sdk.models.schemas.shopping.types import line_item_update_request
+from ucp_sdk.models.schemas.shopping.types.signed_amount import SignedAmount
 from ucp_sdk.models.schemas import payment_handler
 from ucp_sdk.models.schemas.shopping.types import shipping_destination
+from ucp_sdk.models.schemas.shopping.types.totals import Totals
+
+UCP_VERSION = "2026-04-08"
 import uvicorn
 
 
@@ -58,6 +63,42 @@ class UnifiedUpdate(CheckoutUpdateRequest):
   """Client-side unified update model to support extensions."""
 
 
+def _patch_sdk_root_models() -> None:
+  """Make generated April SDK root models test-friendly.
+
+  The April 2026 Python SDK models introduce RootModel wrappers for scalar
+  amounts and for checkout/order totals. These wrappers are correct at the
+  schema layer, but direct iteration/comparison is awkward in the existing
+  conformance assertions.
+  """
+
+  def _scalar_eq(self: Any, other: Any) -> bool:
+    if hasattr(other, "root"):
+      return self.root == other.root
+    return self.root == other
+
+  def _scalar_int(self: Any) -> int:
+    return int(self.root)
+
+  def _scalar_str(self: Any) -> str:
+    return str(self.root)
+
+  Amount.__eq__ = _scalar_eq
+  Amount.__int__ = _scalar_int
+  Amount.__index__ = _scalar_int
+  Amount.__str__ = _scalar_str
+
+  SignedAmount.__eq__ = _scalar_eq
+  SignedAmount.__int__ = _scalar_int
+  SignedAmount.__index__ = _scalar_int
+  SignedAmount.__str__ = _scalar_str
+
+  Totals.__iter__ = lambda self: iter(self.root)
+
+
+_patch_sdk_root_models()
+
+
 FLAGS = flags.FLAGS
 try:
   flags.DEFINE_string("server_url", None, "Base URL of the server")
@@ -480,7 +521,7 @@ def create_checkout_payload(
         payment_handler.PaymentHandler(
           id="google_pay",
           name="google.pay",
-          version="2026-01-23",
+          version=UCP_VERSION,
           spec="https://example.com/spec",
           config_schema="https://example.com/schema",
           instrument_schemas=["https://example.com/instrument_schema"],
@@ -540,7 +581,7 @@ def create_checkout_payload(
       fulfillment=fulfillment,
     )
     checkout_req.status = "incomplete"
-    checkout_req.ucp = {"version": "2026-01-23"}
+    checkout_req.ucp = {"version": UCP_VERSION}
     checkout_req.totals = []
     checkout_req.links = []
 
diff --git a/protocol_test.py b/protocol_test.py
index 4ac7d47..21d8263 100644
--- a/protocol_test.py
+++ b/protocol_test.py
@@ -18,15 +18,20 @@
 import integration_test_utils
 import httpx
 from pydantic import ValidationError
-from ucp_sdk.models.schemas.ucp import BusinessSchema, ReverseDomainName
+from ucp_sdk.models.schemas.ucp import BusinessSchema
 from ucp_sdk.models.schemas.shopping import checkout as checkout
 from ucp_sdk.models.schemas.shopping.payment import (
   Payment,
 )
+from ucp_sdk.models.schemas.shopping.types.reverse_domain_name import (
+  ReverseDomainName,
+)
 
 # Rebuild models to resolve forward references
 checkout.Checkout.model_rebuild(_types_namespace={"Payment": Payment})
 
+UCP_VERSION = "2026-04-08"
+
 
 class ProtocolTest(integration_test_utils.IntegrationTestBase):
   """Tests for UCP protocol compliance.
@@ -162,7 +167,7 @@ def test_discovery(self):
 
     self.assertEqual(
       data.get("version"),
-      "2026-01-23",
+      UCP_VERSION,
       msg="Unexpected UCP version in discovery doc",
     )
 
@@ -223,7 +228,7 @@ def test_discovery(self):
       if isinstance(shopping_services, list)
       else shopping_services
     )
-    self.assertEqual(shopping_service.get("version"), "2026-01-23")
+    self.assertEqual(shopping_service.get("version"), UCP_VERSION)
     self.assertIsNotNone(shopping_service.get("transport") == "rest")
     self.assertIsNotNone(shopping_service.get("endpoint"))
 
@@ -265,7 +270,7 @@ def test_version_negotiation(self):
 
     # 1. Compatible Version
     headers = integration_test_utils.get_headers()
-    headers["UCP-Agent"] = 'profile="..."; version="2026-01-23"'
+    headers["UCP-Agent"] = f'profile="..."; version="{UCP_VERSION}"'
     response = self.client.post(
       checkout_sessions_url,
       json=create_payload.model_dump(
diff --git a/shopping-agent-test.json b/shopping-agent-test.json
index 3617648..84fad37 100644
--- a/shopping-agent-test.json
+++ b/shopping-agent-test.json
@@ -1,13 +1,13 @@
 {
   "ucp": {
-    "version": "2026-01-23",
+    "version": "2026-04-08",
     "capabilities": {
       "dev.ucp.shopping.order": [
         {
           "name": "dev.ucp.shopping.order",
-          "version": "2026-01-23",
-          "spec": "https://ucp.dev/2026-01-23/specification/order/",
-          "schema": "https://ucp.dev/2026-01-23/schemas/shopping/order.json",
+          "version": "2026-04-08",
+          "spec": "https://ucp.dev/2026-04-08/specification/order/",
+          "schema": "https://ucp.dev/2026-04-08/schemas/shopping/order.json",
           "config": {
             "webhook_url": "http://localhost:{webhook_port}/webhooks/partners/test_partner/events/order"
           }