+* masterkey-lui-solr6 is based on Solr 6.x, which requires Java 8. The package
+depends on openjdk-8-jdk, available on backports for
+jessie. openjdk-8-jdk is _not_ available for wheezy. To install
+masterkey-lui-solr6 on wheezy is possible, bu it is outside the scope
+of this document.
+