Security update: Critical Java patch update

What happened On 20 October 2026, Oracle has released an October 2026 Critical Patch Update (https://blogs.oracle.com/security/october-2026-critical-patch-update-released) that includes multiple fixes for Java versions that are in use by Mendix apps. Who is affected All customers with applications running on Mendix Cloud. What we did We have updated the Java version for Java 25 and Java 21. These new versions include the critical patch updates. We're working on updating the other Java versions used on Mendix Cloud (Java 11, Java 17). For these Java versions, we're waiting for an update from our vendors. Once these updates are available, we will update the Java versions used on Mendix Cloud. What you need to do If your app is running on Java 21 or Java 25, you should redeploy your app. You can find the Java version used for your environment on the Environment Details page (https://docs.mendix.com/developerportal/deploy/environments-details/#application-status). You can redeploy the same package that is already running on your environment, or build and deploy a new package. A restart is not enough! We recommend doing this in your usual order, so you can check that your applications still work before updating production: 1. Test environment 2. Acceptance environment 3. Production environment If your app is running on Java 11 or Java 17, you should keep an eye on this Statuspage incident. We will update this when we release new Java versions on Mendix Cloud. These updates will include instructions for the specific Java versions. Deployment requirements To apply these security fixes, you must perform a regular deployment (non-Zero Downtime Deployment). Zero Downtime Deployment (ZDT) will not apply these security fixes, even when redeploying an existing deployment package. You do not need to create a new deployment package. You can redeploy your existing package using the regular deployment process. If you have already performed a Zero Downtime Deployment to apply these fixes, please redeploy using the regular deployment process. A regular deployment causes a short period of downtime while the application restarts, so please plan accordingly. If you have any questions, feel free to contact support.