diff --git a/pgpainless-core/src/test/java/org/pgpainless/example/ModifyKeys.java b/pgpainless-core/src/test/java/org/pgpainless/example/ModifyKeys.java
index e0e8c7fe..5caff9b1 100644
--- a/pgpainless-core/src/test/java/org/pgpainless/example/ModifyKeys.java
+++ b/pgpainless-core/src/test/java/org/pgpainless/example/ModifyKeys.java
@@ -1,14 +1,33 @@
+/*
+ * Copyright 2021 Paul Schaub.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.pgpainless.example;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.security.InvalidAlgorithmParameterException;
 import java.security.NoSuchAlgorithmException;
+import java.util.Date;
+import java.util.List;
 
 import org.bouncycastle.openpgp.PGPException;
+import org.bouncycastle.openpgp.PGPPublicKey;
 import org.bouncycastle.openpgp.PGPSecretKeyRing;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -16,6 +35,7 @@ import org.pgpainless.PGPainless;
 import org.pgpainless.algorithm.EncryptionPurpose;
 import org.pgpainless.algorithm.KeyFlag;
 import org.pgpainless.exception.WrongPassphraseException;
+import org.pgpainless.key.OpenPgpV4Fingerprint;
 import org.pgpainless.key.generation.KeySpec;
 import org.pgpainless.key.generation.type.KeyType;
 import org.pgpainless.key.generation.type.ecc.EllipticCurve;
@@ -23,6 +43,7 @@ import org.pgpainless.key.info.KeyRingInfo;
 import org.pgpainless.key.protection.SecretKeyRingProtector;
 import org.pgpainless.key.protection.UnlockSecretKey;
 import org.pgpainless.util.Passphrase;
+import org.pgpainless.util.TestUtils;
 
 public class ModifyKeys {
 
@@ -107,16 +128,32 @@ public class ModifyKeys {
         assertFalse(info.isUserIdValid("another@user.id"));
     }
 
+    /**
+     * This example demonstrates how to add an additional subkey to an existing key.
+     * Prerequisites are a {@link SecretKeyRingProtector} that is capable of unlocking the primary key of the existing key,
+     * and a {@link Passphrase} for the new subkey.
+     *
+     * There are two way to add a subkey into an existing key;
+     * Either the subkey gets generated on the fly (see below),
+     * or the subkey already exists. In the latter case, the user has to provide
+     * {@link org.bouncycastle.openpgp.PGPSignatureSubpacketVector PGPSignatureSubpacketVectors} for the binding signature
+     * manually.
+     *
+     * Once the subkey is added, it can be decrypted using the provided subkey passphrase.
+     *
+     * @throws PGPException
+     * @throws InvalidAlgorithmParameterException
+     * @throws NoSuchAlgorithmException
+     */
     @Test
     public void addSubkey() throws PGPException, InvalidAlgorithmParameterException, NoSuchAlgorithmException {
         // Protector for unlocking the existing secret key
         SecretKeyRingProtector protector = SecretKeyRingProtector.unlockAllKeysWith(Passphrase.fromPassword(originalPassphrase), secretKey);
         Passphrase subkeyPassphrase = Passphrase.fromPassword("subk3yP4ssphr4s3");
-        assertEquals(1, new KeyRingInfo(secretKey).getEncryptionSubkeys(EncryptionPurpose.STORAGE_AND_COMMUNICATIONS).size());
         secretKey = PGPainless.modifyKeyRing(secretKey)
                 .addSubKey(
                         KeySpec.getBuilder(KeyType.ECDH(EllipticCurve._BRAINPOOLP512R1))
-                                .withKeyFlags(KeyFlag.ENCRYPT_COMMS, KeyFlag.ENCRYPT_STORAGE)
+                                .withKeyFlags(KeyFlag.ENCRYPT_COMMS)
                                 .withDefaultAlgorithms(),
                         subkeyPassphrase,
                         protector)
@@ -126,7 +163,52 @@ public class ModifyKeys {
         KeyRingInfo info = PGPainless.inspectKeyRing(secretKey);
         assertEquals(4, info.getSecretKeys().size());
         assertEquals(4, info.getPublicKeys().size());
-        assertEquals(2, info.getEncryptionSubkeys(EncryptionPurpose.STORAGE_AND_COMMUNICATIONS).size());
+        List<PGPPublicKey> encryptionSubkeys = info.getEncryptionSubkeys(EncryptionPurpose.COMMUNICATIONS);
+        assertEquals(2, encryptionSubkeys.size());
+        UnlockSecretKey.unlockSecretKey(secretKey.getSecretKey(encryptionSubkeys.get(1).getKeyID()), subkeyPassphrase);
+    }
 
+    /**
+     * This example demonstrates how to set a key expiration date.
+     * The provided expiration date will be set on each user-id certification signature.
+     *
+     * @throws PGPException
+     */
+    @Test
+    public void setKeyExpirationDate() throws PGPException {
+        Date expirationDate = TestUtils.getUTCDate("2030-06-24 12:44:56 UTC");
+
+        SecretKeyRingProtector protector = SecretKeyRingProtector
+                .unlockAllKeysWith(Passphrase.fromPassword(originalPassphrase), secretKey);
+        secretKey = PGPainless.modifyKeyRing(secretKey)
+                .setExpirationDate(expirationDate, protector)
+                .done();
+
+
+        KeyRingInfo info = PGPainless.inspectKeyRing(secretKey);
+        assertEquals(TestUtils.formatUTCDate(expirationDate), TestUtils.formatUTCDate(info.getPrimaryKeyExpirationDate()));
+        assertEquals(TestUtils.formatUTCDate(expirationDate), TestUtils.formatUTCDate(info.getExpirationDateForUse(KeyFlag.ENCRYPT_COMMS)));
+        assertEquals(TestUtils.formatUTCDate(expirationDate), TestUtils.formatUTCDate(info.getExpirationDateForUse(KeyFlag.SIGN_DATA)));
+    }
+
+    @Test
+    public void setSubkeyExpirationDate() throws PGPException {
+        Date expirationDate = TestUtils.getUTCDate("2032-01-13 22:30:01 UTC");
+
+        SecretKeyRingProtector protector = SecretKeyRingProtector
+                .unlockAllKeysWith(Passphrase.fromPassword(originalPassphrase), secretKey);
+        secretKey = PGPainless.modifyKeyRing(secretKey)
+                .setExpirationDate(
+                        new OpenPgpV4Fingerprint(secretKey.getPublicKey(encryptionSubkeyId)),
+                        expirationDate,
+                        protector
+                )
+                .done();
+
+
+        KeyRingInfo info = PGPainless.inspectKeyRing(secretKey);
+        assertNull(info.getPrimaryKeyExpirationDate());
+        assertNull(info.getExpirationDateForUse(KeyFlag.SIGN_DATA));
+        assertEquals(TestUtils.formatUTCDate(expirationDate), TestUtils.formatUTCDate(info.getExpirationDateForUse(KeyFlag.ENCRYPT_COMMS)));
     }
 }