This answer from https://online.prognosis.com/forum/us-ask-the-experts/webview-when-only-using-prognosis-on-hp-nonstop/#p176
Good question. From your perspective if you are running Prognosis 9.1, the Web Application in 9.1 runs on various other web servers including on NonStop, as in this P9.1 Help article.
System Guide > User Interfaces > Web Interface > Deployment of Web Interface Application > Deployment Examples
This has changed with Prognosis 10. In Prognosis 10 the Web UI requires particular versions of IIS and Windows only as per this P10 Help article.
Deployment and Installation > Installation > Web Application > System Requirements
You would therefore need a Windows platform to run the Web UI, and potentially a license change if it does not include a Windows server. You would need to discuss this with your account manager to confirm.