diff --git a/pom.xml b/pom.xml
index 198252e..141f2ff 100644
--- a/pom.xml
+++ b/pom.xml
@@ -75,7 +75,7 @@ We use these goals frequently to keep the dependencies and plugins up-to-date:
         <dependency>
             <groupId>org.pcollections</groupId>
             <artifactId>pcollections</artifactId>
-            <version>2.1.2</version>
+            <version>4.0.2</version>
         </dependency>
         <dependency>
             <groupId>org.functionaljava</groupId>