Help centre / Watching
It looks at the software your website reveals (web server, PHP, WordPress, libraries) and compares it with official end-of-life dates, and checks HTTPS and security headers. It tells you what to upgrade and why.
Scans run automatically (weekly on Free, daily on paid plans) and you can click Scan now in Improve → Website health. The server check (Layer 2) also reports your language version automatically.