diff --git a/src/op-cli-installer/github-action/cli-installer/windows-signature.test.ts b/src/op-cli-installer/github-action/cli-installer/windows-signature.test.ts
index 2d41b5b..cc376f4 100644
--- a/src/op-cli-installer/github-action/cli-installer/windows-signature.test.ts
+++ b/src/op-cli-installer/github-action/cli-installer/windows-signature.test.ts
@@ -72,6 +72,28 @@ describe("verifyAuthenticodeSignature", () => {
 			/expected publisher EKU.*not found/,
 		);
 	});
+
+	it("loose mode passes for a Sectigo-issued cert (no Microsoft CS AOC CA issuer)", async () => {
+		const runner = powershellRunner(
+			buildAuthenticodeOutput({
+				issuer:
+					"CN=Sectigo Public Code Signing CA R36, O=Sectigo Limited, C=GB",
+				ekus: ["1.3.6.1.5.5.7.3.3"],
+			}),
+		);
+		await expect(
+			verifyAuthenticodeSignature(OP_EXE, runner, false),
+		).resolves.toBeUndefined();
+	});
+
+	it("loose mode still rejects an unsigned or wrong-publisher binary", async () => {
+		const runner = powershellRunner(
+			buildAuthenticodeOutput({ subject: "CN=Attacker, O=Attacker, C=US" }),
+		);
+		await expect(
+			verifyAuthenticodeSignature(OP_EXE, runner, false),
+		).rejects.toThrow(/does not contain CN=Agilebits/);
+	});
 });
 
 describe("isAzureSignedEra", () => {
diff --git a/src/op-cli-installer/github-action/cli-installer/windows-signature.ts b/src/op-cli-installer/github-action/cli-installer/windows-signature.ts
index 4083361..b170746 100644
--- a/src/op-cli-installer/github-action/cli-installer/windows-signature.ts
+++ b/src/op-cli-installer/github-action/cli-installer/windows-signature.ts
@@ -38,12 +38,19 @@ const defaultPowerShellRunner = async (script: string): Promise<string> => {
 	return stdout;
 };
 
-// Strict Authenticode check against 1Password's Azure Trusted Signing cert.
-// Throws unless Status is Valid, signer is AgileBits, issuer is a Microsoft
-// CS AOC CA, and the publisher EKU is present.
+// Authenticode check against 1Password's signing cert.
+//
+// Strict mode (default, for Azure Trusted Signing era): throws unless Status
+// is Valid, signer is AgileBits, issuer is a Microsoft CS AOC CA, and the
+// publisher EKU is present.
+//
+// Loose mode (for Sectigo era, pre-v2.31.0): only checks Status is Valid and
+// signer is AgileBits. The Sectigo-issued cert has no Microsoft issuer and no
+// publisher EKU, so the strict checks don't apply.
 export const verifyAuthenticodeSignature = async (
 	opExePath: string,
 	runPowerShell: (script: string) => Promise<string> = defaultPowerShellRunner,
+	strict = true,
 ): Promise<void> => {
 	// Read the four Authenticode fields we validate below.
 	const escapedPath = opExePath.replace(/'/g, "''");
@@ -56,6 +63,8 @@ export const verifyAuthenticodeSignature = async (
 	].join("; ");
 
 	const output = await runPowerShell(script);
+	// TEMPORARY DEBUG — remove before merging.
+	console.info(`Authenticode raw output:\n${output}`);
 	const outputLines = output.split("\n").map((l) => l.trim());
 
 	const fieldValue = (prefix: string): string | undefined => {
@@ -82,6 +91,12 @@ export const verifyAuthenticodeSignature = async (
 		);
 	}
 
+	// Loose mode (Sectigo era) stops here. Sectigo certs aren't issued by a
+	// Microsoft CS AOC CA, so the strict issuer check below doesn't apply.
+	if (!strict) {
+		return;
+	}
+
 	// Confirm the cert was issued by Microsoft's expected code signing CA.
 	const issuer = fieldValue("Issuer=") ?? "";
 	if (!issuer.includes(`CN=${WINDOWS_ISSUER_CN_PREFIX}`)) {
diff --git a/src/op-cli-installer/github-action/cli-installer/windows.test.ts b/src/op-cli-installer/github-action/cli-installer/windows.test.ts
index b23a38c..aca1600 100644
--- a/src/op-cli-installer/github-action/cli-installer/windows.test.ts
+++ b/src/op-cli-installer/github-action/cli-installer/windows.test.ts
@@ -16,9 +16,6 @@ jest.mock("./windows-signature", () => ({
 	verifyAuthenticodeSignature: jest.fn().mockResolvedValue(undefined),
 	isAzureSignedEra: jest.fn().mockReturnValue(true),
 }));
-jest.mock("./gpg-signature", () => ({
-	verifyGpgSignature: jest.fn().mockResolvedValue(undefined),
-}));
 
 afterEach(() => {
 	jest.restoreAllMocks();
diff --git a/src/op-cli-installer/github-action/cli-installer/windows.ts b/src/op-cli-installer/github-action/cli-installer/windows.ts
index 3f6530d..d43ac73 100644
--- a/src/op-cli-installer/github-action/cli-installer/windows.ts
+++ b/src/op-cli-installer/github-action/cli-installer/windows.ts
@@ -9,7 +9,6 @@ import {
 	cliUrlBuilder,
 	type SupportedPlatform,
 } from "./cli-installer";
-import { verifyGpgSignature } from "./gpg-signature";
 import type { Installer } from "./installer";
 import {
 	isAzureSignedEra,
@@ -40,14 +39,14 @@ export class WindowsInstaller extends CliInstaller implements Installer {
 
 		core.info("Verifying 1Password CLI signature");
 		const opExePath = path.join(extractedPath, "op.exe");
-		if (isAzureSignedEra(this.version)) {
-			await verifyAuthenticodeSignature(opExePath);
-		} else {
-			await verifyGpgSignature(
-				opExePath,
-				path.join(extractedPath, "op.exe.sig"),
-			);
-		}
+		// Azure-era (v2.31.0+): strict Authenticode (matches current docs).
+		// Sectigo-era (pre-v2.31.0): loose Authenticode (Subject + Status only;
+		// the Sectigo cert lacks the Microsoft issuer and publisher EKU).
+		await verifyAuthenticodeSignature(
+			opExePath,
+			undefined,
+			isAzureSignedEra(this.version),
+		);
 		core.info("1Password CLI signature verified");
 
 		core.addPath(extractedPath);