Merge branch '5.3'

diff --cc package.xml
index 58bb1c68a6b9dbfa7baecb3dd6cf31f49d9d5ae3,55d6297a1333cd3877c5e09170f9f61ec6ce97d1..f03baad845f1db7af74e4bf62f121f8490cf26b9
--- 1/package.xml
--- 2/package.xml
+++ b/package.xml
@@@ -5,8 -5,8 +5,8 @@@
                <packagename language="de">WoltLab Suite Core: Konversationen</packagename>
                <packagedescription>Private conversations between multiple users</packagedescription>
                <packagedescription language="de">Private Konversationen zwischen mehreren Benutzern</packagedescription>
 -              <version>5.3.6</version>
 +              <version>5.4.0 Alpha 1</version>
-               <date>2021-01-08</date>
+               <date>2021-04-14</date>
        </packageinformation>
        
        <authorinformation>