Apple has stopped producing 512GB, 1TB SSD iMac 4K models, claim sources
Apple has reportedly stopped production of the 512 gigabyte and 1 terabyte flash media configurations of the 21.5-inch iMac, which may signify an update is coming sooner rather than later.

Credit: Apple
Long-time AppleInsider sources familiar with Apple's supply chain have told us that Apple has stopped producing the 512GB and 1TB SSD configurations of the iMac 4K. Additionally, both models are newly listed as "currently unavailable" on Apple's website. The 256GB SSD model and the 1TB Fusion Drive model remain available for purchase as of writing, albeit with some lead time.
Given that other iMac 4K models are currently available, it's unclear precisely why Apple has stopped production on the two models, but the production stop may herald a refresh sooner in 2021 than previously thought. Apple has been repeatedly said to be working on redesigned iMacs for 2021, including models to replace both the 21.5-inch and 27-inch iMac.
A new iMac could have a design reminiscent of the Pro Display XDR and could come in new color options. Historically, for both the shift to Intel from PowerPC and the early days of the Intel to Apple Silicon shift, Apple has stuck with existing enclosure designs for the first model, before modifying the exterior to better accomodate new technologies.
In theory, Apple could keep the Fusion Drive and 256GB models available for education and enterprise customers, while refreshing the iMac. There's currently no solid release timeline for the updated iMacs other than sometime in 2021.
Apple last refreshed the 21.5-inch iMac in early 2019 with faster processors, beefier storage options, and improved graphics capabilities. The 27-inch iMac, on the other hand, was updated in August 2020.

Credit: Apple
Long-time AppleInsider sources familiar with Apple's supply chain have told us that Apple has stopped producing the 512GB and 1TB SSD configurations of the iMac 4K. Additionally, both models are newly listed as "currently unavailable" on Apple's website. The 256GB SSD model and the 1TB Fusion Drive model remain available for purchase as of writing, albeit with some lead time.
Given that other iMac 4K models are currently available, it's unclear precisely why Apple has stopped production on the two models, but the production stop may herald a refresh sooner in 2021 than previously thought. Apple has been repeatedly said to be working on redesigned iMacs for 2021, including models to replace both the 21.5-inch and 27-inch iMac.
A new iMac could have a design reminiscent of the Pro Display XDR and could come in new color options. Historically, for both the shift to Intel from PowerPC and the early days of the Intel to Apple Silicon shift, Apple has stuck with existing enclosure designs for the first model, before modifying the exterior to better accomodate new technologies.
In theory, Apple could keep the Fusion Drive and 256GB models available for education and enterprise customers, while refreshing the iMac. There's currently no solid release timeline for the updated iMacs other than sometime in 2021.
Apple last refreshed the 21.5-inch iMac in early 2019 with faster processors, beefier storage options, and improved graphics capabilities. The 27-inch iMac, on the other hand, was updated in August 2020.
Comments
PLEASE, PLEASE, PLEASE, PLEASE, PLEASE, PLEASE, PLEASE, PLEASE, PLEASE,
and 30 inch iMac with M2 later this year?
WINTER 2020 = M1 MBA/MBP 13"
SPRING 2021 = M1 iMac (low-end)
FALL 2021 = M1x MBP 14"/16" and M1x iMac (higher-end)
SPRING 2022 = M1x iMac Pro and Mxe MacPro
That leaves Tuesday, Wednesday, and Thursday. Historically Silicon Valley used Tuesday as the main announcement day to accommodate weekly trade periodical deadlines.
Apple generally gives 7-14 days of lead time to journalists about an impending marketing event. It is late Tuesday 2 March 2021 (Pacific Time Zone) so next week (starting Sunday 7 March) is effectively wiped out for a media event.
That would leave the following week and beyond. However, this is March, the third month of the quarter and Apple rarely makes product announcements right before the quarter is up. Note that Apple's quarters are typically thirteen weeks long (always ending on the last Saturday of the period in question). That rules out the week of March 21-27.
Thus we are left with the week of March 14th. Any product announcements would have a higher chance of occurring on Tuesday 16 March or Wednesday 17 March. It is important to stress that Apple is under no obligation to hold a media event. New product launches have been done by written press release only.
There are two other factors that might reduce the chances of a March announcement. One is the recent squeeze in semiconductor supply. That's not a problem that will go away next month but delaying an announcement by a couple of weeks would increase launch inventory. This is coupled with the recent supply chain hiatus due to the lunar new year. Factory output was curtailed for 2-3 weeks in February which would impact a major product release.
it’s generally assumed that Apple will release a upgraded ‘M1x’ processor at some point. They may use that for the lower end iMac, or they may simply release the low end iMac with the M1 and give the 5k version the beefier processor.
Then later, perhaps we'll see higher-end configs with M1X and more RAM.
I love the iMac, and have owned them in the past. But, I simply won't have a single-use display in the mix any longer. I guess I'm not the target market for the iMac, then, but I easily could be. And, since Apple has no reasonably-priced display, it would be an easy win for them as well. Buy this new Apple monitor, and get an M1 Mac thrown in as well.