The smartphone market will decline overall in 2019, but sales will begin to improve during the second half of the year as 5G devices slowly begin to make inroads with customers — a process that will take years, not months. That’s the key set of predictions from research firm IDC, citing the latest edition of its Worldwide Quarterly Mobile Phone Tracker.

Though a handful of 5G phones were announced at last month’s Mobile World Congress in Barcelona, aggregate shipments of 6.7 million 5G devices are expected to represent only 0.5 percent of the total 1.395 billion phones that will be shipped in 2019 — around one-eighth as many 5G phones as 3G phones. But by 2023, the situation will be reversed: 5G phones will represent 26 percent of all shipments, with the aging 3G technology declining to represent only 2.2 percent of the market.

IDC’s estimates suggest that 4G phones aren’t going anywhere for the foreseeable future. They’ll still have an estimated 95.4 percent of the market this year, and 71.4 percent of an even larger 1.542 billion phone market four years from now.

“Though the 5G developments and foldable screen buzz is yet to have a reality check from users,” explained IDC senior analyst Sangeetika Srivastava, “2019 will be surely marked as a year of modernization in the smartphone market.” The firm expects that 5G marketing will quickly ramp up and begin to make stronger cases for device upgrades, leading 5G to represent one in every four smartphone sales by 2023.

Notably, these projections come solely from currently available information, and are subject to dramatic changes. IDC’s prediction that 2019 will be the third year of declining smartphone sales is based in part upon current political concerns, slow growth in China, and longer upgrade cycles, all of which could turn around if the U.S.-China trade war was resolved and tariff-inflated prices dropped. Similarly, lowered prices or greater network availability could improve the uptake of 5G devices more quickly than the firm anticipates.