How can I update macOS Sierra on iMac?
how can I update my Sierra OS?
[Re-Titled by Moderator]
iMac, macOS 10.13
Question marked as
You can update at the very least to High Sierra (has same requirement as SIerra), but depending on your Model / Year of Mac will be whether you can update any further than that.
You can download the High Sierra installer from the following support document.
click here ➜ How to download and install macOS - Apple Support
Mojave is the followup to High Sierra, and you need at least one of the computers listed in the page linked below to update to it.
click here ➜ macOS Mojave - Technical Specifications