I have two older 20" iMacs, a Mid 2007 and a Early 2009, that I've handed down to my kids. Both are running 10.10. Last night they both popped up a notification to upgrade to 10.14. Clearly these are unsupported devices. I'm trying to figure out if it is something that I did to cause this or if it was just a glitch from Apple's servers. The 2007 has been upgraded with a faster CPU and SSD, but as far as I remember the 2009 is all stock (I put an SSD in it at one point but it always hung booting - apparently that chipset is very picky about what SSD's it likes so I put the original HD back in). I didn't get the notification on my unsupported 2011 Air running 10.13. Is anyone else getting these notifications on machines new enough to run 10.8+ with the notification center?