This is a re-post from Scott Butler in the FAQ section - but it's worth mentioning here:
You should update the application server directly, and never attempt to just overwrite files from other installs, as it may cause inconsistencies or problems.
Steps to update to the latest public release:
1. Open a terminal/shell or command prompt and navigate your root Servoy install directory
Windows:
Choose Start -> Run, and type 'cmd' to launch your command prompt. Then navigate to the Servoy install directory. Ex:
cd "C:\Program Files\Servoy"
Mac
Open Terminal application at /Applications/Utilities . Then navigate to the Servoy install directory. Ex:
cd /Applications/Servoy
2. Run this command
java -jar servoy_updater.jar