Hours after Apple discontinued the iMac Pro, the company has also discontinued two configurations of the 4K 21.5-inch iMac. The 512GB and 1TB SSD configurations are no longer available. Both options became unavailable for purchase last month, but it wasn't clear if this was a temporary problem.
But now, the company has removed both SSD options for the iMac's configuration page completely. With Apple rumoured to launch a redesigned iMac this year, it isn't that surprising that the company is phasing out older models.
Source: MacRumors