diff --git a/hapi-fhir-base/pom.xml b/hapi-fhir-base/pom.xml
index 56c9c60c676..fe23ce7e48c 100644
--- a/hapi-fhir-base/pom.xml
+++ b/hapi-fhir-base/pom.xml
@@ -91,6 +91,10 @@
 			<groupId>commons-codec</groupId>
 			<artifactId>commons-codec</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>org.apache.commons</groupId>
+			<artifactId>commons-collections4</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>commons-io</groupId>
 			<artifactId>commons-io</artifactId>