Sold a 4 year old iMac model - Has anyone had this issue in the past?   

Are you sure that it isn't an "iMac Pro"?

The iMac Pro was released in 2017 and it was discontinued in March 2021 but was sold by Apple until early 2021.

See: Identify your iMac model - Apple Support

You are confusing computer model years with car model years. The latter traditionally change yearly. In Apple computers, a year represents a feature set, not the year it was made. My 2017 5K iMac I received at the end of October 2018 shows it was manufactured the week of 10-22-2018, ~18 months after its introduction.

A classic example was the very popular Mid 2012 Macbook Pro 13-inch non-Retina was in continuous production from June 2012 through Oct 2016 and, after that, remained available from the refurb store for a while.

About this:

About this mac: iMac 21.5-inch, 2017.

Does "About this Mac.. include the phrase, "Retina 4K?"

Converting CAD1679 to US gives USD1233 with today's exchange rates. As the slower business/education non-Retina version sold for USD1099 before taxes and fees and the faster standard consumer model sold for USD1299 before taxes and fees, I suspect you have the slower model. And that model was continuously manufactured new as late as Oct 2021.

It was current at the time of purchase – but only because it was a low-end "price point" model. Even in 2017, you sacrificed a lot by buying the cheap model: a Retina screen, a quad-core CPU, and a discrete GPU. Nonetheless, that was a tradeoff that some institutional buyers were willing to make.

MacTracker shows that the final three 21.5" Intel-based iMacs were:

• iMac (21.5-inch, 2017) – June 2017 to October 2021
• iMac (Retina 4K, 21.5-inch, 2017) – June 2017 to March 2019
• iMac (Retina 4K, 21.5-inch, 2019) – March 2019 to April 2021

In May of 2021, Apple came out with the first Apple Silicon iMac: the iMac (24-inch, M1, 2021). It also had a Retina screen (a 4.5K one). The 24" M1 iMac hung around until October 2023.

So the "price point" model stuck around for the whole lifetime of two of the regular models, and part of the lifetime of a third. Presumably, the priorities of institutional "price point" buyers were the reason it hung around so long.

mfsh wrote:

It's about the inability to upgrade past OS Ventura because it is dated 2017 even though it was sold to me in 2021. It's doesn't make sense. I can upgrade my macbook air that I purchased NEW in 2019 to Sonoma.

What matters in terms of ability to upgrade is the hardware model, and hardware model year. Not the date of manufacture.

All of the non-Retina 21.5-inch iMacs sold between June 2017 and October 2021 have the same basic internal design. There might have been small component substitutions here and there, e.g. Apple might have sourced hard drives or RAM chips from several different suppliers. But as for main components like the CPU, GPU, and motherboard chip set, Apple would have used the same sets of components over the life of the model.

If Apple had changed those components, it would typically be in the context of introducing a new model. E.g., going from "Kaby Lake" CPUs in the 2017 iMacs to "Coffee Lake" CPUs in the 2019 models.

FoxFifth wrote:

Are you sure that it isn't an "iMac Pro"?

+1 Good question.

Actually, maybe not a good question. A 2017 iMac Pro should be able to upgrade to the latest macOS Sequoia 15.5.

To the original poster, what does your iMac show at Apple menu > About this Mac?

When you next decide to upgrade your iMac consider the following: a 10 Core Mac Mini M4 with 16 GB RAM and 1 TB SSD with a 32" LG 4k monitor w/speakers is $1418 w/tax which is $650 less than a similarly configured new 24" iMac.

The above is at today's prices.

I got one to replace my aging 2017 17" iMac. Best Mac I've had to date.

Just some food for thought.

FWIW, your iMac was manufactured until October 2021. So it was current at the time of purchase.

mfsh wrote:

It only states IMAC 21.5" on the invoice - no mention of "Pro".

A 21.5" iMac couldn't be an iMac Pro. All of those had 27" 5K Retina screens. They looked much like 27" iMacs, except that their cases were Space Gray instead of Silver. Inside, they had Intel Xeon workstation CPUs with 8 to 18 cores, high-end GPUs, and fast SSDs. Prices started at $4999 USD.

Basically, nice machines to read about, but if you were a home user who had to ask "How much does one cost?", the answer was "You can't afford it. Buy a regular iMac instead!"

mfsh wrote:

I paid full price $1,679.00. I truly thought I was purchasing a 2021 model that would last. My bad luck.

What you paid and what you thought are immaterial. It had nothing to do with luck. You chose from what was currently available at the time. You could have purchased a 21.5" 4K or 27" 5K 2019 iMac at the time.

It's not that much bigger than a 27" (26" width vs 28" width) but gives me more real estate when running at a lower resolution (for larger text size) for these aging eyes of mine. Remember the stated size of a monitor is the diagonal size which is larger than the width. Sneaky TV and monitor manufactures.

Allan Jones wrote:

A classic example was the very popular Mid 2012 Macbook Pro 13-inch non-Retina was in continuous production from June 2012 through Oct 2016 and, after that, remained available from the refurb store for a while.

That was one of the last two MacBook Pros to feature

• User-upgradable RAM
• A 2.5" SATA drive bay (for the startup drive, which could be a HDD or SSD). (It couldn't take the faster PCIe SSDs, but you could upgrade the startup drive, which was not always true of the early Retina MacBook Pros until OWC found sources for compatible parts.)
• A built-in optical drive
• FireWire 800. It was only of a small handful of Macs to have the then-very-desirable combination of FireWire 800, USB 3, and Thunderbolt 1. Most Macs that have USB 3 or better do not have FireWire.

It stayed in the product line three years longer than its 15" sibling did.