diff --git a/SECURITY.md b/SECURITY.md
index 9c1ddf7ff..a45b6faa5 100644
--- a/SECURITY.md
+++ b/SECURITY.md
@@ -7,9 +7,9 @@ significant impact. However, should an issue be identified, I
 will strive to fix these issues as soon as possible.
 
 Fixes will be released as a new version, built from the most
-recent `main` branch for Java 17, and from the `v4` branch for
-Java 11 backwards compatibility. Unless expressly requested,
-no attempt to backport changes will be made.
+recent `main` branch for Java 17. Support will not automatically
+be provided for v5 or v4 versions of the library, but can be
+requested if necessary via an issue.
 
 Given this library is designed for use in test packs, the main
 design assumption is that the software is being used by a
diff --git a/java-compiler-testing/pom.xml b/java-compiler-testing/pom.xml
index b22d73f16..ac97ddd1a 100644
--- a/java-compiler-testing/pom.xml
+++ b/java-compiler-testing/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>io.github.ascopes.jct</groupId>
     <artifactId>java-compiler-testing-parent</artifactId>
-    <version>5.0.5-SNAPSHOT</version>
+    <version>6.0.0-SNAPSHOT</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
 
diff --git a/java-compiler-testing/src/test/java/io/github/ascopes/jct/assertions/AbstractContainerGroupAssertTest.java b/java-compiler-testing/src/test/java/io/github/ascopes/jct/assertions/AbstractContainerGroupAssertTest.java
index 01a6c9fc8..9c37985ac 100644
--- a/java-compiler-testing/src/test/java/io/github/ascopes/jct/assertions/AbstractContainerGroupAssertTest.java
+++ b/java-compiler-testing/src/test/java/io/github/ascopes/jct/assertions/AbstractContainerGroupAssertTest.java
@@ -25,7 +25,6 @@
 import static org.mockito.Mockito.when;
 
 import io.github.ascopes.jct.containers.ContainerGroup;
-import java.util.List;
 import java.util.ServiceLoader;
 import java.util.stream.Stream;
 import org.assertj.core.api.AbstractListAssert;
@@ -164,6 +163,7 @@ public T get() {
     }
 
     @Override
+    @SuppressWarnings("unchecked")
     public Class<? extends T> type() {
       return (Class<T>) service.getClass();
     }
diff --git a/java-compiler-testing/src/test/java/io/github/ascopes/jct/utils/SpecialLocationsUtilsTest.java b/java-compiler-testing/src/test/java/io/github/ascopes/jct/utils/SpecialLocationsUtilsTest.java
index cf00c655a..e7521284d 100644
--- a/java-compiler-testing/src/test/java/io/github/ascopes/jct/utils/SpecialLocationsUtilsTest.java
+++ b/java-compiler-testing/src/test/java/io/github/ascopes/jct/utils/SpecialLocationsUtilsTest.java
@@ -76,7 +76,6 @@ public Class<?> getTypeBeingTested() {
   }
 
   @DisplayName("javaRuntimeLocations() returns the JRT location")
-  @EnabledForJreRange(min = JRE.JAVA_9, disabledReason = "unavailable without JPMS")
   @Test
   void javaRuntimeLocationsReturnsTheJrtLocation() {
     // When
diff --git a/pom.xml b/pom.xml
index 3030359cc..32e13faf1 100644
--- a/pom.xml
+++ b/pom.xml
@@ -21,7 +21,7 @@
 
   <groupId>io.github.ascopes.jct</groupId>
   <artifactId>java-compiler-testing-parent</artifactId>
-  <version>5.0.5-SNAPSHOT</version>
+  <version>6.0.0-SNAPSHOT</version>
   <packaging>pom</packaging>
 
   <name>Java Compiler Testing parent project</name>
@@ -93,7 +93,7 @@
     <awaitility.version>4.3.0</awaitility.version>
     <fuzzywuzzy.version>1.4.0</fuzzywuzzy.version>
     <jspecify.version>1.0.0</jspecify.version>
-    <junit.version>5.13.4</junit.version>
+    <junit.version>6.0.0</junit.version>
     <memoryfilesystem.version>2.8.1</memoryfilesystem.version>
     <mockito.version>5.20.0</mockito.version>
     <slf4j.version>2.0.17</slf4j.version>
@@ -379,7 +379,6 @@
             <bottom>© ${project.inceptionYear} - ${current-year}, Ashley Scopes --
               Apache License V2
             </bottom>
-            <defaultSince>0.0.1</defaultSince>
             <detectLinks>false</detectLinks>
             <header>
               <![CDATA[