diff --git a/CHANGELOG.md b/CHANGELOG.md
index 279fada19..080054259 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 ###Changelog
 
+####Version 1.6.3
+* bug fixes
+
 ####Version 1.6.2
 * fixed issues with connection time out when server does not support ping
 
diff --git a/build.gradle b/build.gradle
index c5fb8381e..a434faabc 100644
--- a/build.gradle
+++ b/build.gradle
@@ -48,7 +48,7 @@ android {
 	defaultConfig {
 		minSdkVersion 14
 		targetSdkVersion 21
-		versionCode 86
+		versionCode 87
 		versionName "1.7.0-alpha"
 	}
 
diff --git a/src/main/java/eu/siacs/conversations/utils/MimeUtils.java b/src/main/java/eu/siacs/conversations/utils/MimeUtils.java
index a9e89d1b7..d45444240 100644
--- a/src/main/java/eu/siacs/conversations/utils/MimeUtils.java
+++ b/src/main/java/eu/siacs/conversations/utils/MimeUtils.java
@@ -458,7 +458,7 @@ public final class MimeUtils {
         if (extension == null || extension.isEmpty()) {
             return null;
         }
-        return extensionToMimeTypeMap.get(extension);
+        return extensionToMimeTypeMap.get(extension.toLowerCase());
     }
     /**
      * Returns true if the given extension has a registered MIME type.