Merge branch '5.5' into 6.0

diff --cc fileDelete.xml
index 2be00043cd62a2a48025f5911fad64a34cd153da,b4f0cc0d771f7392afe951366fbc18292a5f900c..7a6c9a0a6eae6553b2e2830cbbde8857ce7d62a7
--- 1/fileDelete.xml
--- 2/fileDelete.xml
+++ b/fileDelete.xml
@@@ -9,9 -7,9 +9,10 @@@
                <file>acp/update_com.woltlab.wcf.conversation_3.1_addColumn.php</file>
                <file>acp/update_com.woltlab.wcf.conversation_5.2.php</file>
                <file>acp/update_com.woltlab.wcf.conversation_5.4_deleteLanguageItems.php</file>
 +              <file>acp/update_com.woltlab.wcf.conversation_5.5_cleanup_orphaned_attachments.php</file>
                <file>js/WoltLab/Conversation/UI/Participant/Add.js</file>
                <file>js/WoltLab/Conversation/Ui/Participant/Add.js</file>
+               <file>js/require.build.js</file>
                <file>js/require.build.min.js</file>
                <file>lib/form/ConversationMessageAddForm.class.php</file>
                <file>lib/form/ConversationMessageEditForm.class.php</file>