4.9

🚀 New features and improvements

• Allow setting of custom websocket headers (#458) @agentgonzo
• JENKINS-40700 - Enable Launcher to hold the communication protocol. (#452) @Aki-7

🐛 Bug fixes

• Define hudsonUrl in WebSocket mode to fix agent installers (#454) @jglick

📦 Dependency updates

• Update Guava (#456) @jglick