Upgrade from Sierra to High Sierra
My Mac is currently on 10.12.6. I just decided recently it was time to upgrade but I can't go to 10.14 - apparrenlty my Mac is too old. So I thought I would at least go to 10.13. I did obtain 10.13.6 but it requires 10.13 to install it.
iMac 21.5", macOS 10.12