The next Apple Watch will probably be super popular

Apple became the biggest wearable vendor this May thanks to a recent surge in Apple Watch sales. Now, experts are saying the Watch could continue to see explosive sales heading into 2018.

A new report from Taiwanese publication Digitimes says Apple Watch shipments are expected to increase to 4.5 million units in the fourth quarter of this year and could reach 15 million units shipped by the end of the year. It also projects volume to rise to 20 million units in 2018, citing sources from the upstream supply chain.

One of the big reasons the Apple Watch could see an uptick in sales is because of the expected addition of 4G LTE cellular connectivity, which means that the device won't need to be paired with an iPhone in order to work.

The Apple Watch might also get a major makeover, although it's less likely. Most experts agree that Apple will instead offer consumers performance upgrades to the popular second-generation Watch along with the new LTE-connected units.

Those improvements and the new cellular connectivity is likely make the device more attractive to the general market, according to analysts, which could kick off a sales frenzy as the LTE Apple Watch becomes seen as a must-have gadget.

Even for a company like Apple, these growth numbers are impressive. The first generation Watch only shipped 5 million units total in 2015, according to the Digitimes report. The company is now doing nearly as much business in just one quarter, with the second-generation Watch picking up the slack.

It's important to note that all of these shipment totals are just estimates, though, since Apple refuses to release actual Apple Watch sales numbers. We do know that the device's sales were up 50 percent from last year as of the company's latest quarterly earning's report, according to Tim Cook, so these DigiTimes projections probably won't be too far off the mark.

The Apple Watch's growth could be the first sign of the resurgent wearables market, which is expected to be entering a "new phase," according to IDC. The market is projected to hit 240.1 million shipments in total by 2021 — and you can bet that a good chunk of those will come from Apple.