Clean install
all done in one hour 30 minutes (off-line)
no data lose
system requirements
macos high sierra has the same requirements as its predecessor:
imac: late 2009 or newer
macbook/macbook (retina): late 2009 or newer
macbook pro: mid-2010 or newer
macbook air: late 2010 or newer
mac mini: mid-2010 or newer
mac pro: mid-2010 or newer
imac pro: 2017