diff --git a/CHANGES.txt b/CHANGES.txt
index e2614ec3f8..aa00edd417 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,5 +1,7 @@
 3.0.21
  * Run evictFromMembership in GossipStage (CASSANDRA-15592)
+Merged from 2.2
+ * Allow EXTRA_CLASSPATH to work on tar/source installations (CASSANDRA-15567)
 
 3.0.20
  * Run in-jvm upgrade dtests in circleci (CASSANDRA-15506)
@@ -20,7 +22,8 @@
  * Ensure legacy rows have primary key livenessinfo when they contain illegal cells (CASSANDRA-15365)
  * Fix race condition when setting bootstrap flags (CASSANDRA-14878)
  * Fix NativeLibrary.tryOpenDirectory callers for Windows (CASSANDRA-15426)
-Merged from 2.2
+
+2.2.16
  * Fix SELECT JSON output for empty blobs (CASSANDRA-15435)
  * In-JVM DTest: Set correct internode message version for upgrade test (CASSANDRA-15371)
  * In-JVM DTest: Support NodeTool in dtest (CASSANDRA-15429)
diff --git a/bin/cassandra b/bin/cassandra
index bc949e03ce..f887b31f5f 100755
--- a/bin/cassandra
+++ b/bin/cassandra
@@ -27,6 +27,7 @@
 # behavior, those variables are:
 #
 #   CLASSPATH -- A Java classpath containing everything necessary to run.
+#   EXTRA_CLASSPATH -- A Java classpath with anything to be appended to CLASSPATH
 #   JVM_OPTS -- Additional arguments to the JVM for heap size, etc
 #   JVM_ON_OUT_OF_MEMORY_ERROR_OPT -- The OnOutOfMemoryError JVM option if specified
 #   CASSANDRA_CONF -- Directory containing Cassandra configuration files.
diff --git a/bin/cassandra.in.sh b/bin/cassandra.in.sh
index 92f79c7d46..13b1291f65 100644
--- a/bin/cassandra.in.sh
+++ b/bin/cassandra.in.sh
@@ -48,6 +48,9 @@ done
 for jsr223jar in "$CASSANDRA_HOME"/lib/jsr223/*/*.jar; do
     CLASSPATH="$CLASSPATH:$jsr223jar"
 done
+
+CLASSPATH="$CLASSPATH:$EXTRA_CLASSPATH"
+
 # JSR223/JRuby - set ruby lib directory
 if [ -d "$CASSANDRA_HOME"/lib/jsr223/jruby/ruby ] ; then
     export JVM_OPTS="$JVM_OPTS -Djruby.lib=$CASSANDRA_HOME/lib/jsr223/jruby"