diff --git a/.github/workflows/continuous-integration.yaml b/.github/workflows/continuous-integration.yaml
index 82b288e..2d9d8cb 100644
--- a/.github/workflows/continuous-integration.yaml
+++ b/.github/workflows/continuous-integration.yaml
@@ -14,7 +14,6 @@ jobs:
       max-parallel: 2
       matrix:
         java:
-          - '8'
           - '11'
           - '17'
         os:
diff --git a/.github/workflows/upstream.yaml b/.github/workflows/upstream.yaml
index 13e0ade..6d7b0e2 100644
--- a/.github/workflows/upstream.yaml
+++ b/.github/workflows/upstream.yaml
@@ -16,7 +16,6 @@ jobs:
       max-parallel: 2
       matrix:
         java:
-          - '8'
           - '11'
           - '17'
     runs-on: ubuntu-latest
diff --git a/asciidoctorj-pdf/build.gradle b/asciidoctorj-pdf/build.gradle
index d92f092..a50309e 100644
--- a/asciidoctorj-pdf/build.gradle
+++ b/asciidoctorj-pdf/build.gradle
@@ -28,7 +28,6 @@ dependencies {
   gems "rubygems:text-hyphen:$textHyphenVersion"
   gems "rubygems:ttfunk:$ttfunkGemVersion"
   gems "rubygems:css_parser:$cssParserGemVersion"
-  gems "rubygems:rexml:$rexmlGemVersion"
 
   testImplementation "org.apache.pdfbox:pdfbox:$pdfboxVersion"
 }
diff --git a/asciidoctorj-pdf/gradle.properties b/asciidoctorj-pdf/gradle.properties
index 4e36b77..62a2327 100644
--- a/asciidoctorj-pdf/gradle.properties
+++ b/asciidoctorj-pdf/gradle.properties
@@ -1,4 +1,4 @@
 properName=AsciidoctorJ PDF
 description=AsciidoctorJ PDF bundles the Asciidoctor PDF RubyGem (asciidoctor-pdf) so it can be loaded into the JVM using JRuby.
-version=2.3.17
+version=2.3.18
 gem_name=asciidoctor-pdf
diff --git a/build.gradle b/build.gradle
index 6978434..0c7b8bb 100644
--- a/build.gradle
+++ b/build.gradle
@@ -12,13 +12,19 @@ buildscript {
     mavenCentral()
     maven { url "https://oss.sonatype.org/content/repositories/snapshots/" }
   }
+  dependencies {
+    classpath("com.github.jruby-gradle:jruby-gradle-plugin:2.0.1") {
+      exclude module: 'grolifant'
+      exclude module: 'okhttp-digest'
+    }
+    classpath 'org.ysb33r.gradle:grolifant:0.17.0'
+  }
 }
 
 // modern plugins config
 plugins {
   id "signing"
   id "io.github.gradle-nexus.publish-plugin" version "1.1.0"
-  id 'com.github.jruby-gradle.base' version '2.0.0'
 }
 
 // TIP use -PpublishRelease=true to active release behavior regardless of the version
@@ -31,14 +37,14 @@ ext {
   statusIsRelease = (status == 'release')
 
   // jar versions
-  jrubyVersion = '9.4.0.0'
+  jrubyVersion = '9.4.8.0'
   pdfboxVersion = '3.0.0'
   junitVersion = '5.10.0'
   assertjVersion = '3.24.2'
 
   // gem versions
   asciidoctorJVersion = project.hasProperty('asciidoctorJVersion') ? project.asciidoctorJVersion : '2.5.7'
-  asciidoctorPdfGemVersion = project.hasProperty('asciidoctorPdfGemVersion') ? project.asciidoctorPdfGemVersion : '2.3.17'
+  asciidoctorPdfGemVersion = project.hasProperty('asciidoctorPdfGemVersion') ? project.asciidoctorPdfGemVersion : '2.3.18'
 
   addressableVersion = '2.8.0'
   concurrentRubyVersion = '1.1.7'
@@ -46,7 +52,6 @@ ext {
   prawnGemVersion=project.hasProperty('prawnGemVersion') ? project.prawnGemVersion : '2.4.0'
   prawnSvgGemVersion = "0.34.1"
   rghostGemVersion = '0.9.7'
-  rexmlGemVersion = '3.2.6'
   threadSafeGemVersion = '0.3.6'
   ttfunkGemVersion = '1.7.0'
   cssParserGemVersion = '1.12.0'
diff --git a/gradle.properties b/gradle.properties
index fd0f77b..1c321af 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,4 +1,4 @@
-version=2.3.17
+version=2.3.18
 sourceCompatibility=1.8
 targetCompatibility=1.8