9to5Mac published a story that an anonymous Twitter suggests that Apple has an update for the iMac and Mac mini coming soon. 

New Mac mini and iMac updates coming 'soon' alongside new iPad, leaker says

An anonymous Twitter user who has previously leaked numerous accurate details about Apple’s product lineups has returned today. This time, the source suggests that that Apple has an update for the iMac and Mac mini coming soon. Details here are unknown, but CoinX on Twitter says to expect updates to both of Apple’s consumer-level Mac models “soon.”

New Mac mini and iMac updates coming 'soon' alongside new iPad, leaker says - 9to5Mac