It looks like slower user upgrade cycles will plague the carriers a bit longer.

According to a Tuesday report from Gartner, device life cycles extending two years or more are likely to stick around for the next half decade in mature markets like North America, Western Europe and Japan.

"In the mature markets, premium phone users are extending life cycles to 2.5 years, which is not going to change drastically over the next five years," said Gartner research director Roberta Cozza.

Gartner said the shift to longer device life cycles stems from both the carriers’ move away from subsidies in favor of equipment installment plans and a trend toward more minor upgrades in premium devices.

"These programs are not for everyone, as most users are happy to hold onto their phone for two years or longer than before,” Cozza said. “They do so especially as the technology updates have become incremental rather than exponential.”

The upgrade cycle is also slow in emerging markets, where premium phones have an average life span of 2.2 years to 2.5 years and basic phones have an average life span of three years or more.

But there is some opportunity in opening up these markets.

According to Cozza, smartphone sales in Sub-Saharan Africa overtook those of feature phones for the first time in 2015.

“This region represents an attractive market for vendors that can persuade users to migrate to their first smartphone," Cozza said.

The battle for sales, though, will be a fierce one. Gartner on Tuesday reaffirmed its previous prediction that global smartphone sales growth will slow to just seven percent to 1.5 billion units in 2016. The firm said smartphone sales are expected to grow in the single digits over the next several years to hit 1.9 billion units in 2020.