Later this week, Apple (NASDAQ:AAPL) is hosting an event at which it is expected to unveil new MacBook computers. What wasn't clear -- at least until now -- was whether the company would make next-generation iMac desktop computers available alongside the new MacBook computers.

Apple's current iMac lineup. Image source: Apple. 

According to KGI Securities analyst Ming-Chi Kuo, the answer to that question is "no."

Kuo says that his team expects Apple to release updated 21.5-inch and 27-inch iMacs in the middle of the first half of 2017. That, at least to this Fool, seems to suggest that they will launch in the March-to-April timeframe -- perhaps not so coincidentally around the time that Apple held its "Spring Forward" event earlier this year.

That makes a ton of sense. Here's why.

Apple shouldn't update the iMac until Kaby Lake launches

The current MacBook Air and MacBook Pro computers use old processor technology from Intel (NASDAQ:INTC). The Air machines use Intel's fifth-generation Core processors, which launched back in early 2015. Intel has been shipping its sixth-generation Core processors for quite some time and is currently rolling out its seventh-generation Core processors.

The MacBook Pro line is a mixed bag; the 13-inch MacBook Pro uses a fifth-generation Core processor, but the 15-inch MacBook Pro still uses a fourth-generation Core processor.

The bottom line is that the MacBook Pro computers need to be upgraded at this point.

In contrast, Apple's iMac lineup is in better shape in this regard. The 27-inch iMacs use Intel's sixth-generation Core processors -- the latest desktop processors currently available -- while the 21.5-inch models use a fifth-generation Core processor.

Apple simply can't deliver a processor upgrade for the 27-inch iMac until early next year, when Intel's seventh-generation Core processors for desktops are expected to be available. The 21.5-inch model could potentially be updated to a sixth-generation Core processor at the October event, but it would be very strange for Apple to update just one model now.

Apple's Mac business should have several good quarters

Apple's Mac business should get a much-needed shot in the arm with the launch of the new MacBook systems during the October event. Apple should be able to help keep the Mac's momentum up with the launch of the new iMacs early next year.

Going forward, if Apple can deliver new Mac systems at roughly an annual cadence, then it should be able to defend, if not grow, its market share within the world of personal computers going forward. However, if the company lets its Mac products stagnate again, then it risks the resumption of the market share losses it has suffered in recent quarters.

Although Apple's overall revenues and profits are still dominated by sales of its iPhone line of smartphones, the Mac is still an important part of its business. During its last fiscal year, Apple's Mac product line was responsible for more than $25 billion in revenue -- more than 10% of the $233.7 billion in revenue that the company took in during that time.

Apple doesn't live or die by the Mac, but until there is convincing evidence that the company's iPhone business will return to growth, the company can't afford any self-inflicted wounds to any of its major operating segments. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.