# System/Developer Requirements

Source: [https://docs.virtosoftware.com/docs/calendar-overlay-pro/administration-and-system-requirements/system-developer-requirements/](https://docs.virtosoftware.com/docs/calendar-overlay-pro/administration-and-system-requirements/system-developer-requirements/)


## **Operating System**

Microsoft 365 / SharePoint Online, Microsoft Teams, Outlook, and the Microsoft 365 app. For host-specific setup and mobile support, see [Opening Virto Calendar in Microsoft Teams, Outlook, and the Microsoft 365 app](/docs/calendar-overlay-pro/installation-and-configuration/adding-virto-calendar-app-to-the-site-page/#opening-virto-calendar-in-microsoft-teams-outlook-and-the-microsoft-365-app).

## **Browser**

Microsoft Edge, Microsoft Internet Explorer 11, Google Chrome, Mozilla Firefox.