diff --git a/changelog.d/policyengine-uk-2.88.21.changed.md b/changelog.d/policyengine-uk-2.88.21.changed.md
new file mode 100644
index 0000000..7fd7538
--- /dev/null
+++ b/changelog.d/policyengine-uk-2.88.21.changed.md
@@ -0,0 +1 @@
+Update policyengine-uk to 2.88.21.
diff --git a/pyproject.toml b/pyproject.toml
index 8979458..8fa0ff6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -12,7 +12,7 @@ dependencies = [
     "supabase>=2.10.0",
     "storage3>=0.8.1",
     "policyengine==4.4.4",
-    "policyengine-uk==2.88.14",
+    "policyengine-uk==2.88.21",
     "policyengine-us==1.691.3",
     "pydantic>=2.9.2",
     "pydantic-settings>=2.6.0",
diff --git a/uv.lock b/uv.lock
index 2f0d796..467c139 100644
--- a/uv.lock
+++ b/uv.lock
@@ -1918,7 +1918,7 @@ wheels = [
 
 [[package]]
 name = "policyengine-api-v2"
-version = "0.6.6"
+version = "0.6.10"
 source = { editable = "." }
 dependencies = [
     { name = "alembic" },
@@ -1972,7 +1972,7 @@ requires-dist = [
     { name = "logfire", extras = ["fastapi", "httpx", "sqlalchemy"], specifier = ">=0.60.0" },
     { name = "modal", specifier = ">=0.68.0" },
     { name = "policyengine", specifier = "==4.4.4" },
-    { name = "policyengine-uk", specifier = "==2.88.14" },
+    { name = "policyengine-uk", specifier = "==2.88.21" },
     { name = "policyengine-us", specifier = "==1.691.3" },
     { name = "psycopg2-binary", specifier = ">=2.9.10" },
     { name = "pydantic", specifier = ">=2.9.2" },
@@ -2023,7 +2023,7 @@ wheels = [
 
 [[package]]
 name = "policyengine-uk"
-version = "2.88.14"
+version = "2.88.21"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "microdf-python" },
@@ -2031,9 +2031,9 @@ dependencies = [
     { name = "pydantic" },
     { name = "tables" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/8c/2b/ab82aa30c5d27176fd9d449ff5ed9708d0080b00912f7dc2efa0af0fd87e/policyengine_uk-2.88.14.tar.gz", hash = "sha256:21a4387ae52dcb5430b6d790edcc321816ed47147a3a0e21ffd482a36834d352", size = 1185947, upload-time = "2026-05-09T04:19:25.284Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/67/f3/583fb5be4536c82a4ab6fcefe56db65e2e06e2f933a11fb42c122707e1f1/policyengine_uk-2.88.21.tar.gz", hash = "sha256:1504692fb45ddb721dc1472da73bbcd490cc2b102352df03f298d5c4a6fe4a25", size = 1190946, upload-time = "2026-05-23T12:08:16.003Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/a3/fc/276fb639a46bda35523329d8968bcc4089fde9e97fab82722c0ec853c6cc/policyengine_uk-2.88.14-py3-none-any.whl", hash = "sha256:ed10005ba7d0c973c0966ebbf7672853fb3caaa0456b8bf485fb13f8c323d975", size = 1913671, upload-time = "2026-05-09T04:19:23.364Z" },
+    { url = "https://files.pythonhosted.org/packages/29/05/9707e2e30e1d9e77a436d6db2914eabc151b45a6c400e0b85d35b42d9c9c/policyengine_uk-2.88.21-py3-none-any.whl", hash = "sha256:bbd8f49fa081d0fb44278f684bd355bb1f5a56dcfdb49b13260c1ecba8e0c428", size = 1919741, upload-time = "2026-05-23T12:08:13.878Z" },
 ]
 
 [[package]]