diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index ef5afa1e3..cc860cca8 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -30,12 +30,9 @@ jobs:
     # Many tests only pass on Windows
     runs-on: windows-latest
 
-    # On Java 11, continue on error to upload artifact
-    continue-on-error: ${{ matrix.java == '11' }}
-
     strategy:
       matrix:
-        java: [ '11', '17' ]
+        java: [ '11', '21' ]
 
     name: Java ${{ matrix.java }} build
 
@@ -59,7 +56,7 @@ jobs:
         uses: actions/upload-artifact@v4
         if: ${{ failure() }}
         with:
-          name: test-output
+          name: test-output-${{ matrix.java }}
           path: |
             echosvg-test/build/reports/tests/test/
             test-references/samples/**/candidate-variation/*
diff --git a/README.md b/README.md
index 1dc688cb0..1f7483121 100644
--- a/README.md
+++ b/README.md
@@ -29,7 +29,7 @@ To build EchoSVG you need the following software installed:
 - The [Git version control system](https://git-scm.com/downloads) is required to
 obtain the sources. Any recent version should suffice.
 
-- Java 11 or 17 (later versions may work but aren't tested by CI). You can install
+- Java version 11 to 21 (later versions may work but aren't tested by CI). You can install
 it from your favourite package manager or by downloading from [Adoptium](https://adoptium.net/).
 
 <br/>
diff --git a/echosvg-svgrasterizer/build.gradle b/echosvg-svgrasterizer/build.gradle
index 76680bcf8..10253503b 100644
--- a/echosvg-svgrasterizer/build.gradle
+++ b/echosvg-svgrasterizer/build.gradle
@@ -18,6 +18,9 @@ dependencies {
 
 test {
 	useJUnitPlatform()
+	if (JavaVersion.current() > JavaVersion.VERSION_11) {
+		systemProperty('java.security.manager', 'allow')
+	}
 }
 
 tasks.processTestResources{
diff --git a/echosvg-test/build.gradle b/echosvg-test/build.gradle
index 1a4fc54ea..05a0456be 100644
--- a/echosvg-test/build.gradle
+++ b/echosvg-test/build.gradle
@@ -83,6 +83,12 @@ test {
 	}
 }
 
+tasks.withType(Test) {
+	if (JavaVersion.current() > JavaVersion.VERSION_11) {
+		systemProperty('java.security.manager', 'allow')
+	}
+}
+
 tasks.withType(ProcessResources).configureEach {
 	dependsOn ':echosvg-test-scripts:copyScriptJars',':echosvg-test-scripts:copyPolicyJar'
 }
diff --git a/gradle.properties b/gradle.properties
index 72692d590..091852f37 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -13,5 +13,3 @@ htmlParserVersion=1.4.16
 jclfTextVersion=5.0.1
 junitVersion=5.10.3
 jmhVersion=1.37
-# Allow Security Manager
-systemProp.java.security.manager=allow