diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f7fc6d4..5d857e0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -28,10 +28,10 @@ jobs:
 
     steps:
       - uses: actions/checkout@v6
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: actions/setup-java@v5
         with:
-          java-version: '21'
+          java-version: '25'
           distribution: 'corretto'
 
       - name: Build with Maven
diff --git a/pom.xml b/pom.xml
index a714fa2..355091a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -5,12 +5,12 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>4.0.0</version>
+        <version>4.0.3</version>
         <relativePath/> <!-- lookup parent from repository -->
     </parent>
     <groupId>cf.maybelambda</groupId>
     <artifactId>http-validator</artifactId>
-    <version>3.0.3</version>
+    <version>4.0.0</version>
     <name>http-validator</name>
     <description>Retrieves target HTTP resources and responses, validates them and notifies about their current status.</description>
 
@@ -63,7 +63,7 @@
     </dependencies>
 
     <properties>
-        <java.version>21</java.version>
+        <java.version>25</java.version>
         <snippetsDirectory>${project.build.directory}/generated-snippets</snippetsDirectory>
     </properties>
 
diff --git a/src/docs/asciidocs/api-guide.adoc b/src/docs/asciidocs/api-guide.adoc
index 2db2cec..077984d 100644
--- a/src/docs/asciidocs/api-guide.adoc
+++ b/src/docs/asciidocs/api-guide.adoc
@@ -186,12 +186,12 @@ Finally, run
 java -jar target/http-validator-x.y.z.jar
 ----
 
-**NOTE:** If more than one version of Java is installed on the host a suitable one (**v21+**) might need to be specified
+**NOTE:** If more than one version of Java is installed on the host a suitable one (**v25+**) might need to be specified
 instead of the default before running the commands above, i.e.
 
 [source,bash]
 ----
-export JAVA_HOME=/usr/lib/jvm/java-21-openjdk
+export JAVA_HOME=/usr/lib/jvm/java-25-openjdk
 ./mvnw...
 /path/to/java -jar...
 ----