VPL Jail System 5.0.3

VPL Jail System 5.0.3 is a maintenance release focused on stability, compatibility, and reliability.

October 5, 2026 · Download the vpl-jail-system-5.0.3.tar.gz package (218 KB) from GitHub

Download the vpl-jail-system-5.0.3.tar.gz package (218 KB) from server

More reliable connections

Communication between VPL and the Jail Server has been improved.

• Improves WebSocket communication for text data by handling invalid UTF-8 sequences.
• Fixes an issue where duplicate cookies could interrupt communication.
• Improves compatibility of the VPL_Iwh cookie used to secure web application execution.
• Optimizes communication wait times for better responsiveness and resource usage.
• Fixes an issue that could cause an unnecessary time-status message to be sent after a task had already stopped.

Improved installation and upgrades

• Improves package installation and error reporting.
• Improves compatibility with Linux distributions that use dnf.
• Automatically updates service configuration after upgrades.
• Adds the install-vpl-ls.sh script for LS installation.
• Adds support for installing LS during Docker builds.

Improved logging

• Moves log files to /var/log/vpl.
• Logs routine events related to WebSocket closures, task cleanup, and zombie task cleanup at the INFO or DEBUG level.
• Adds a standard access log to vpl-jail-server.log as a starting point for accountability and auditing of executed tasks.

Fixes

• Fixes compatibility issues with 32-bit systems.
• Refactors the locking mechanism to use global and task-level locks.
• Resolves PTY compatibility issues.

Better support for graphical applications

VNC support has been improved for activities that require a graphical desktop or graphical applications.

• Improves TigerVNC installation.
• Improves VNC startup reliability.
• Improves error reporting when a graphical session cannot be started.
• Improves graphical session startup speed.

Improved Java/JUnit support

The Hamcrest package is now included as a dependency required by JUnit, improving support for Java programming activities that use JUnit tests.

Recommended update

Updating to VPL Jail Server 5.0.3 is recommended for installations using previous 5.0 releases, particularly for sites using graphical activities, JUnit, or web applications, as well as sites that have experienced intermittent communication or startup issues.