Only one mapping for each current system property name is allowed.

Author: epugh

solr/solrj/src/resources/DeprecatedSystemPropertyMappings.properties

@@ -3,6 +3,7 @@
 # You do not need a entry for a solrMyProperty to solr.my.property conversion
 # However, if you are renaming solrMyProperty to solr.my.special.property, then use solr.my.property for the legacy name
 # We have inverted the meaning of some properties, and therefore they have a =! pattern to facilitate backwards compatibility
+# Only one mapping for each current system property name is allowed.
 
 # To be removed in Solr 12:
 
@@ -19,7 +20,7 @@ solr.cloud.shardsplit.checkdiskspace.enabled=solr.shard.split.check.disk.space.e
 solr.cloud.prep.recovery.read.timeout.additional.ms=prep.recovery.read.timeout.extra.wait
 solr.cloud.prs.enabled=solr.prs.default
 solr.cloud.delete.unknown.cores.enabled=solr.delete.unknown.cores
-solr.cloud.delete.unknown.cores.enabled=solr.cloud.startup.delete.unknown.cores.enabled
+#solr.cloud.delete.unknown.cores.enabled=solr.cloud.startup.delete.unknown.cores.enabled
 solr.cloud.wait.for.zk.seconds=solr.wait.for.zk
 
 solr.configset.bootstrap.confdir=bootstrap_confdir