Please upload the latest Cassandra packages (3.11.4) to stretch-wikimedia, component/cassandra311:
dget http://dl.bintray.com/apache/cassandra/pool/main/c/cassandra/cassandra_3.11.4_all.deb dget http://dl.bintray.com/apache/cassandra/pool/main/c/cassandra/cassandra-tools_3.11.4_all.deb dget -d http://dl.bintray.com/apache/cassandra/pool/main/c/cassandra/cassandra_3.11.4.dsc
See also: https://gerrit.wikimedia.org/r/c/operations/puppet/+/543494