diff --git a/pom.xml b/pom.xml
index 22be29f..2556569 100644
--- a/pom.xml
+++ b/pom.xml
@@ -135,7 +135,7 @@
       <dependency>
         <groupId>com.io7m.jaffirm</groupId>
         <artifactId>com.io7m.jaffirm.core</artifactId>
-        <version>4.0.0</version>
+        <version>4.0.1</version>
       </dependency>
       <dependency>
         <groupId>com.io7m.jranges</groupId>