If you are looking to perform the update described in the story, here is the technical breakdown of the steps Elias took:

Yes, only if your Mac supports Catalina. High Sierra (10.13.6) can go directly to Catalina (10.15) via the Software Update pane or the Catalina installer.

Search App Store for “macOS Monterey” or “macOS Big Sur.” If the installer allows it, download and run directly from High Sierra. If not, the installer will tell you to update to an intermediate version (Catalina).

Updating from macOS High Sierra 10.13.6 to macOS Catalina 10.15 is a significant jump that modernizes your Mac’s security and feature set. However, the loss of 32-bit app support is a major consideration. If you have critical older software, stay on High Sierra or upgrade to Mojave (10.14) instead. For everyone else, follow this guide carefully, always backup first, and enjoy a newer, faster, and more secure macOS experience.

"Are you sure you want to download macOS Catalina?" the prompt asked.

macOS Catalina (10.15) runs on these Macs:

High Sierra (10.13.6) will not always show Catalina in the standard "Software Update" section because it is not the latest version available (Big Sur, Monterey, Ventura, etc., are newer).