MacOS High Sierra Patcher, the successor to macOS Sierra Patcher, is an easy-to-use tool that allows anyone to install macOS High Sierra on unsupported Macs. What's new in macOS High Sierra Patcher Version 2.7.0. If you recently upgraded to Mac OS X High Sierra (10.13.1), you may not be able to connect to the Internet (over Wi-Fi or Ethernet) including unable to browse web pages or open the App Store. Additionally, your Mac will display “ green ” in System Preferences and show a connected Wi-Fi signal indicating you have a network connection. This means that if you decide to upgrade now, the only OS you’ll be able to go back to is El Capitan. We kindly advise you to consider this before upgrading and make sure you’ll be willing to keep High Sierra for the next year. Can your Mac update macOS this time? Here are all the Mac models that are fit to run the latest OS 10.13. Sep 25, 2017 I have a mid-2010 MacPro. I'm trying to install High Sierra, but I keep getting this message: 'To install macOS High Sierra, a firmware update is required.' I can't find any firmware updates. I've tried holding the start button down several times, but I still get the message.