diff --git a/pgpainless-core/src/test/kotlin/org/pgpainless/key/KeyWithUnsupportedSignatureSubpacketTest.kt b/pgpainless-core/src/test/kotlin/org/pgpainless/key/KeyWithUnsupportedSignatureSubpacketTest.kt
new file mode 100644
index 00000000..e557adc3
--- /dev/null
+++ b/pgpainless-core/src/test/kotlin/org/pgpainless/key/KeyWithUnsupportedSignatureSubpacketTest.kt
@@ -0,0 +1,38 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.key
+
+import java.util.*
+import org.bouncycastle.openpgp.PGPSecretKeyRing
+import org.junit.jupiter.api.Test
+import org.pgpainless.PGPainless
+import org.pgpainless.key.protection.SecretKeyRingProtector
+
+class KeyWithUnsupportedSignatureSubpacketTest {
+
+    @Test
+    fun `can set new expiration date on key containing unknown subpacket 34`() {
+        val armoredKey =
+            """-----BEGIN PGP PRIVATE KEY BLOCK-----
+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+=YAt0
+-----END PGP PRIVATE KEY BLOCK-----"""
+        val key: PGPSecretKeyRing = PGPainless.readKeyRing().secretKeyRing(armoredKey)!!
+        PGPainless.modifyKeyRing(secretKey = key)
+            .setExpirationDate(Date(), SecretKeyRingProtector.unprotectedKeys())
+            .done()
+    }
+}