diff --git a/fdroidserver/index.py b/fdroidserver/index.py
index f7162092..d3c1a0b7 100644
--- a/fdroidserver/index.py
+++ b/fdroidserver/index.py
@@ -361,9 +361,16 @@ def make_v0(apps, apks, repodir, repodict, requestsdict):
 
         # Check for duplicates - they will make the client unhappy...
         for i in range(len(apklist) - 1):
-            if apklist[i]['versionCode'] == apklist[i + 1]['versionCode']:
-                raise FDroidException("duplicate versions: '%s' - '%s'" % (
-                    apklist[i]['apkName'], apklist[i + 1]['apkName']))
+            first = apklist[i]
+            second = apklist[i + 1]
+            if first['versionCode'] == second['versionCode'] \
+               and first['sig'] == second['sig']:
+                if first['hash'] == second['hash']:
+                    raise FDroidException('"{0}/{1}" and "{0}/{2}" are exact duplicates!'.format(
+                        repodir, first['apkName'], second['apkName']))
+                else:
+                    raise FDroidException('duplicates: "{0}/{1}" - "{0}/{2}"'.format(
+                        repodir, first['apkName'], second['apkName']))
 
         current_version_code = 0
         current_version_file = None
diff --git a/tests/repo/index.xml b/tests/repo/index.xml
index 88507d52..ff958b7b 100644
--- a/tests/repo/index.xml
+++ b/tests/repo/index.xml
@@ -129,7 +129,7 @@
 	<application id="obb.mainpatch.current">
 		<id>obb.mainpatch.current</id>
 		<added>2016-04-23</added>
-		<lastupdated>2016-04-23</lastupdated>
+		<lastupdated>2017-06-01</lastupdated>
 		<name>OBB Main/Patch Current</name>
 		<summary></summary>
 		<icon>obb.mainpatch.current.1619.png</icon>
diff --git a/tests/repo/obb.mainpatch.current_1619_another-release-key.apk b/tests/repo/obb.mainpatch.current_1619_another-release-key.apk
new file mode 100644
index 00000000..1a494fe2
Binary files /dev/null and b/tests/repo/obb.mainpatch.current_1619_another-release-key.apk differ
diff --git a/tests/run-tests b/tests/run-tests
index 931d6e06..84f7f766 100755
--- a/tests/run-tests
+++ b/tests/run-tests
@@ -484,6 +484,28 @@ test -e repo/index-v1.jar
 export ANDROID_HOME=$STORED_ANDROID_HOME
 
 
+#------------------------------------------------------------------------------#
+echo_header "check duplicate files are properly handled by fdroid update"
+
+REPOROOT=`create_test_dir`
+KEYSTORE=$WORKSPACE/tests/keystore.jks
+cd $REPOROOT
+$fdroid init --keystore $KEYSTORE --repo-keyalias=sova
+echo 'keystorepass = "r9aquRHYoI8+dYz6jKrLntQ5/NJNASFBacJh7Jv2BlI="' >> config.py
+echo 'keypass = "r9aquRHYoI8+dYz6jKrLntQ5/NJNASFBacJh7Jv2BlI="' >> config.py
+mkdir $REPOROOT/metadata
+cp -a $WORKSPACE/tests/metadata/obb.mainpatch.current.txt $REPOROOT/metadata
+echo "accepted_formats = ['txt']" >> config.py
+cp $WORKSPACE/tests/repo/obb.mainpatch.current_1619.apk $REPOROOT/repo/
+cp $WORKSPACE/tests/repo/obb.mainpatch.current_1619_another-release-key.apk $REPOROOT/repo/
+$fdroid update --pretty
+grep -F 'obb.mainpatch.current_1619.apk' repo/index.xml
+grep -F 'obb.mainpatch.current_1619_another-release-key.apk' repo/index.xml
+# die if there are exact duplicates
+cp $WORKSPACE/tests/repo/obb.mainpatch.current_1619.apk $REPOROOT/repo/duplicate.apk
+! $fdroid update
+
+
 #------------------------------------------------------------------------------#
 echo_header "setup new repo from scratch using ANDROID_HOME, putting APKs in repo first"
 
diff --git a/tests/stats/known_apks.txt b/tests/stats/known_apks.txt
index 94a40a74..ec777242 100644
--- a/tests/stats/known_apks.txt
+++ b/tests/stats/known_apks.txt
@@ -4,4 +4,5 @@ obb.main.twoversions_1101613.apk obb.main.twoversions 2015-10-12
 obb.main.twoversions_1101615.apk obb.main.twoversions 2016-01-01
 obb.main.twoversions_1101617.apk obb.main.twoversions 2016-06-20
 obb.mainpatch.current_1619.apk obb.mainpatch.current 2016-04-23
+obb.mainpatch.current_1619_another-release-key.apk obb.mainpatch.current 2017-06-01
 urzip-πÇÇπÇÇ现代汉语通用字-български-عربي1234.apk info.guardianproject.urzip 2016-06-23
diff --git a/tests/update.TestCase b/tests/update.TestCase
index be1a7266..3742f965 100755
--- a/tests/update.TestCase
+++ b/tests/update.TestCase
@@ -204,7 +204,7 @@ class UpdateTest(unittest.TestCase):
         apps = fdroidserver.metadata.read_metadata(xref=True)
         knownapks = fdroidserver.common.KnownApks()
         apks, cachechanged = fdroidserver.update.scan_apks({}, 'repo', knownapks, False)
-        self.assertEqual(len(apks), 6)
+        self.assertEqual(len(apks), 7)
         apk = apks[0]
         self.assertEqual(apk['minSdkVersion'], '4')
         self.assertEqual(apk['targetSdkVersion'], '18')