Index: applications/editors/josm/plugins/build-common.xml
===================================================================
--- applications/editors/josm/plugins/build-common.xml	(revision 34603)
+++ applications/editors/josm/plugins/build-common.xml	(revision 34604)
@@ -195,6 +195,11 @@
             <param name="property.value" value="${plugin.canloadatruntime}"/>
         </antcall>
+        <antcall target="add-manifest-attribute">
+            <param name="manifest.attribute" value="Plugin-Minimum-Java-Version"/>
+            <param name="property.name" value="plugin.minimum.java.version"/>
+            <param name="property.value" value="${plugin.minimum.java.version}"/>
+        </antcall>
         <antcall target="additional-manifest" />
-        <jar destfile="${plugin.jar}" basedir="${plugin.build.dir}" manifest="MANIFEST" manifestencoding="UTF-8">
+        <jar destfile="${plugin.jar}" basedir="${plugin.build.dir}" manifest="MANIFEST" manifestencoding="UTF-8" duplicate="preserve" level="9">
             <restrict>
                 <not><or>
@@ -205,4 +210,5 @@
                     <name name="META-INF/*.RSA"/>
                     <name name="META-INF/*.SF"/>
+                    <name name="module-info.class"/>
                 </or></not>
                 <archives>
@@ -213,6 +219,6 @@
             </restrict>
         </jar>
-        <jar destfile="${plugin.sources.jar}" basedir="${plugin.src.dir}"/>
-        <jar destfile="${plugin.javadoc.jar}" basedir="${plugin.doc.dir}"/>
+        <jar destfile="${plugin.sources.jar}" basedir="${plugin.src.dir}" level="9"/>
+        <jar destfile="${plugin.javadoc.jar}" basedir="${plugin.doc.dir}" level="9"/>
         <delete file="MANIFEST" failonerror="no"/>
         <antcall target="post-dist" />
Index: applications/editors/josm/plugins/openjfx/build.xml
===================================================================
--- applications/editors/josm/plugins/openjfx/build.xml	(revision 34603)
+++ applications/editors/josm/plugins/openjfx/build.xml	(revision 34604)
@@ -12,4 +12,5 @@
     <property name="plugin.class" value="org.openstreetmap.josm.plugins.jaxb.OpenJfxPlugin"/>
     <property name="plugin.description" value="Provides the OpenJFX (JavaFX) library for JOSM core and other JOSM plugins. Provides additional features such as MP3 audio playback."/>
+    <property name="plugin.minimum.java.version" value="11"/>
     <!--<property name="plugin.icon" value="..."/>-->
     <!--<property name="plugin.link" value="..."/>-->