How To Update Macos High Sierra 10136 To 1015 ((full)) -

Here’s a step-by-step guide to update from macOS High Sierra 10.13.6 (the final version of 10.13) to macOS Catalina 10.15.

Your Mac must be one of the following models to officially support macOS Catalina: MacBook: Early 2015 or newer MacBook Air: Mid 2012 or newer MacBook Pro: Mid 2012 or newer Mac mini: Late 2012 or newer iMac: Late 2012 or newer iMac Pro: 2017 or newer Mac Pro: Late 2013 or newer 2. Prepare Your Mac

Catalina supports Macs introduced mid‑2012 or later for many models; older Macs that run High Sierra may not be supported. Check exact model year (About This Mac > System Report) against Catalina system requirements before attempting the upgrade.
If your Mac is unsupported, you cannot upgrade to Catalina without unofficial patches (not recommended).

Supported models for macOS Catalina (10.15):