You will be able to launch the New Upgrade as well as use the Sandbox Mode only if you are a user having Site Owner (Full Control) permissions on the site.
Therefore, from the safety point of view, launching New Upgrade is protected from unauthorized access.
Related articles:
Main articles about New Upgrade:
- ShortPoint SPFx New Upgrade for Office 365 and SharePoint 2019
- ShortPoint SPFx Auto Upgrade Feature
- ShortPoint SPFx Sandbox Mode Feature
You may check other FAQs about ShortPoint Upgrade in this folder.