Rerunning a preflight optimization
If you change the access group's portal, the application, or the application’s skin after running the preflight optimization process, repeat the preflight optimization to remove any unnecessary static content or add necessary static content introduced by your changes.
When you move your application between different versions of Pega Platform, to optimize your content and improve application load time, rerun the optimization on the new version of the application, even if the new version does not include any changes. Since the underlying files that the system optimizes may change across versions of Pega Platform, rerunning the optimization is required to ensure that the latest version of your application has the correct content to render and the application load time meets your requirements.
In the header of Dev Studio, click.
On the Preflight Optimization screen, click the Gear icon for the optimized portal.
In the Optimization configuration dialog box, click Submit to repeat the optimization process.