Is that iMac on your desk looking old and crusty? Apple could have new models on the way, judging from how long it's taking for current orders to get shipped from the company's online store right now.

AppleInsider took stock of inventory for the current 21.5- and 27-inch iMac models and noted they appear to be dwindling, suggesting Apple is planning to unveil new versions at next week's Worldwide Developer Conference in San Francisco.

Constrained inventory for older Apple product is historically a good indication a new model is imminent, and the stars appear to be aligning as speculation last month claimed "a new low-cost iMac" was in the cards.

The April prognostication came straight from KGI Securities analyst Ming-Chi Kuo, who also predicted Apple would boost this year's iMac sales to 4.8 million shipments, a 23% increase that could likely only be possible with the arrival of a new model.

Slipping dates

For months, iMac ship times from the US Apple Online Store have been holding steady at "within 24 hours," a timeframe that switched to "three to four business days" over the long Memorial Day weekend.

Buyers hoping for custom configurations such as a faster processor or more RAM are seeing even longer times, with shipping estimates of five to seven business days or as much as 10 business days in many cases.

And it's not just Apple: Many authorized resellers such as MacMall are also showing limited inventory, while e-tailer Amazon.com is completely sold out of the latest models. However, third-party Marketplace vendors have limited stock at this writing.

Apple's last major redesign of the iMac came in late 2012, followed by an internal spec bump the following year; the Mac maker also slashed the base price of its MacBook Air alongside a similar spec bump last month, lending credence to the possibility of a cheaper iMac to come.

  • Will we also see a new iPhone 6 at WWDC? No! But that doesn't mean you can't read all about it now.