diff --git a/integration/modal_app.py b/integration/modal_app.py
index a91851cf..18f6cd94 100644
--- a/integration/modal_app.py
+++ b/integration/modal_app.py
@@ -220,8 +220,18 @@
         # policyengine's bundled data-release manifest certifies an exact
         # country-package version; a newer policyengine-us makes every US
         # (and via import, UK) call raise at import time. Keep this pin in
-        # sync with the manifest version reported by the certification error.
-        "policyengine-us==1.764.6",
+        # sync with the manifest version reported by the certification error
+        # (1.764.6) and with integration/pyproject.toml. PyPI no longer hosts
+        # 1.764.6, so it installs from the policyengine-us commit that set
+        # that version; a wheel built from this archive has the same package
+        # files as the PyPI wheel. Tarball URL, not git+, for the same reason
+        # as us-hank-model below.
+        "policyengine-us @ https://github.com/PolicyEngine/policyengine-us/archive/92e6052d3e057c4e03b955d01a7ee4e3c2fb3131.tar.gz",
+        # Unpinned upstream (policyengine-us 1.764.6 declares
+        # spm-calculator>=0.2.0, policyengine 4.x microdf_python>=1.2.1), so a
+        # rebuild would take newer releases than the image has run with.
+        "spm-calculator==0.3.1",
+        "microdf-python==1.3.0",
         # US HANK (hank_shock / hank_summary). Installed from GitHub as a
         # normal wheel — no data files or repo checkout needed at runtime;
         # the calibration is code. Cost profile: the first hank_shock call
@@ -284,6 +294,21 @@
         f"pip install -e {OBR_REPO} -e {BOE_REPO} -e {FRB_REPO} "
         f"-e {HOME}/macro/integration"
     )
+    # Refresh the two CA lists that the server's outbound HTTPS (Hugging Face
+    # microdata downloads, PolicyEngine data fetches) verifies against:
+    # Debian's ca-certificates, read by urllib, aiohttp and hf-xet, and certifi,
+    # read by requests and httpx. The pip_install layer built on 2026-08-12
+    # held certifi 2026.7.22, on a debian_slim base built before Debian
+    # released ca-certificates 20250419~deb12u2; both lists trusted the
+    # compromised eMudhra root "emSign ECC Root CA - G3"
+    # (https://emudhra.we-have-a-problem.com).
+    # The pip_install layer now rebuilds (its policyengine-us requirement
+    # changed), which would pull the current certifi on its own; these two
+    # explicit steps keep the fixed minimums enforced for any later rebuild,
+    # whatever the layers above resolve to, and refresh the Debian package
+    # regardless of how old Modal's cached debian_slim base layer is.
+    .apt_install("ca-certificates")
+    .pip_install("certifi>=2026.10.19")
 )
 
 app = modal.App("policyengine-macro-mcp")
diff --git a/integration/pyproject.toml b/integration/pyproject.toml
index d411ed2e..32f8de55 100644
--- a/integration/pyproject.toml
+++ b/integration/pyproject.toml
@@ -58,8 +58,18 @@ models = [
     "policyengine[models]>=4,<5",
     # policyengine's bundled data-release manifest certifies an exact
     # policyengine-us version; anything newer fails certification at import
-    # (every pe.* call raises). Keep in sync with the manifest pin.
-    "policyengine-us==1.764.6",
+    # (every pe.* call raises). Keep in sync with the manifest pin, 1.764.6.
+    # PyPI no longer hosts 1.764.6, so it installs from the policyengine-us
+    # commit that set that version (the repository has no release tags); a
+    # wheel built from this archive has the same package files as the PyPI
+    # wheel. It satisfies the policyengine-us==1.764.6 pin in [models].
+    "policyengine-us @ https://github.com/PolicyEngine/policyengine-us/archive/92e6052d3e057c4e03b955d01a7ee4e3c2fb3131.tar.gz",
+    # policyengine-us 1.764.6 declares spm-calculator>=0.2.0 and policyengine
+    # 4.x declares microdf_python>=1.2.1, so a fresh install would take
+    # releases newer than the ones these models were run and certified with.
+    # Pin the versions the deployed image holds.
+    "spm-calculator==0.3.1",
+    "microdf-python==1.3.0",
 ]
 
 [project.scripts]