diff --git a/app/src/main/java/org/fdroid/fdroid/IndexV1Updater.java b/app/src/main/java/org/fdroid/fdroid/IndexV1Updater.java
index 97b82c773..5e702d957 100644
--- a/app/src/main/java/org/fdroid/fdroid/IndexV1Updater.java
+++ b/app/src/main/java/org/fdroid/fdroid/IndexV1Updater.java
@@ -167,20 +167,19 @@ public class IndexV1Updater extends RepoUpdater {
             return;
         }
 
-            /* TODO
-            if (timestamp < repo.timestamp) {
-                throw new RepoUpdater.UpdateException(repo, "index.jar is older that current index! "
-                        + timestamp + " < " + repo.timestamp);
-            }
-            */
-        // TODO handle maxage, convert to "expiration" Date instance
+        long timestamp = (Long) repoMap.get("timestamp") / 1000;
+
+        if (repo.timestamp > timestamp) {
+            throw new RepoUpdater.UpdateException(repo, "index.jar is older that current index! "
+                    + timestamp + " < " + repo.timestamp);
+        }
 
         X509Certificate certificate = getSigningCertFromJar(indexEntry);
         verifySigningCertificate(certificate);
         Utils.debugLog(TAG, "Repo signature verified, saving app metadata to database.");
 
         // timestamp is absolutely required
-        repo.timestamp = (Long) repoMap.get("timestamp");
+        repo.timestamp = timestamp;
         // below are optional, can be null
         repo.name = getStringRepoValue(repoMap, "name");
         repo.icon = getStringRepoValue(repoMap, "icon");
diff --git a/app/src/test/java/org/fdroid/fdroid/updater/IndexV1UpdaterTest.java b/app/src/test/java/org/fdroid/fdroid/updater/IndexV1UpdaterTest.java
index 9967a3113..1bc261142 100644
--- a/app/src/test/java/org/fdroid/fdroid/updater/IndexV1UpdaterTest.java
+++ b/app/src/test/java/org/fdroid/fdroid/updater/IndexV1UpdaterTest.java
@@ -27,7 +27,11 @@ import java.util.jar.JarFile;
 
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.core.IsNot.not;
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.fail;
 
 @Config(constants = BuildConfig.class, sdk = 24)
 @RunWith(RobolectricTestRunner.class)
@@ -41,6 +45,7 @@ public class IndexV1UpdaterTest extends FDroidProviderTest {
     public void testIndexV1Processing() throws IOException, RepoUpdater.UpdateException {
         Preferences.setup(context);
         Repo repo = MultiRepoUpdaterTest.createRepo("Testy", TESTY_JAR, context, TESTY_CERT);
+        repo.timestamp = 1481222110;
         IndexV1Updater updater = new IndexV1Updater(context, repo);
         JarFile jarFile = new JarFile(TestUtils.copyResourceToTempFile(TESTY_JAR), true);
         Log.i(TAG, "jarFile " + jarFile);
@@ -63,6 +68,19 @@ public class IndexV1UpdaterTest extends FDroidProviderTest {
         getClass().getResourceAsStream("foo");
     }
 
+    @Test(expected = RepoUpdater.UpdateException.class)
+    public void testIndexV1WithOldTimestamp() throws IOException, RepoUpdater.UpdateException {
+        Repo repo = MultiRepoUpdaterTest.createRepo("Testy", TESTY_JAR, context, TESTY_CERT);
+        repo.timestamp = System.currentTimeMillis() / 1000;
+        IndexV1Updater updater = new IndexV1Updater(context, repo);
+        JarFile jarFile = new JarFile(TestUtils.copyResourceToTempFile(TESTY_JAR), true);
+        JarEntry indexEntry = (JarEntry) jarFile.getEntry(IndexV1Updater.DATA_FILE_NAME);
+        InputStream indexInputStream = jarFile.getInputStream(indexEntry);
+        updater.processIndexV1(indexInputStream, indexEntry, "fakeEtag");
+        fail(); // it should never reach here, it should throw a SigningException
+        getClass().getResourceAsStream("foo");
+    }
+
     @Test(expected = RepoUpdater.SigningException.class)
     public void testIndexV1WithBadTestyJarNoManifest() throws IOException, RepoUpdater.UpdateException {
         testBadTestyJar("testy.at.or.at_no-MANIFEST.MF_index-v1.jar");