Early 2009 X-Serve? It has a quad-core Xeon processor. [update] I am wrong. It is the late 2008 X-Serve that won't upgrade ... Specs: https://support.apple

Early 2009 X-Serve? It has a quad-core Xeon processor. [update] I am wrong. It is the late 2008 X-Serve that won't upgrade ... Specs: https://support.apple.com/kb/SP10?locale=en_US https://support.apple.com/kb/SP10?locale=en_US Supported H/W: iMac (Mid 2007 or newer) MacBook (Late 2008 Aluminum, or Early 2009 or newer) MacBook Pro (Mid/Late 2007 or newer) MacBook Air (Late 2008 or newer) Mac mini (Early 2009 or newer) Mac Pro (Early 2008 or newer) Xserve (Early 2009) from https://www.apple.com/osx/how-to-upgrade/ https://www.apple.com/osx/how-to-upgrade/