Don’t worry if you’re still hauling around an iPhone 4s — you’re just kinda dated, but not obsolete. Plus, you can still play 2048. But for nearly 40 million other people, there’s reason to finally upgrade from that LG Chocolate or Motorola Razr: the most popular sites on the Internet just won’t work anymore.

Buzzfeed reports forthcoming changes to the encrypted web — namely to big sites like Facebook, Twitter, and Google — will not be compatible with phones more than 5 years old as of January 1. While this doesn’t pose a problem for most city slickers and their fancy-pants phablets and smartphones, it does pose a problem to residents of the developing world, and your Great Uncle Frank, who stands by his Sidekick because of its durability.

“The problem is that people across the world, most of them in the developing world, use old phones or desktops that don’t update themselves, and they won’t be able to access the internet,” Matthew Prince, CEO of CloudFlare, told Buzzfeed News. “For the developing world, on average, 4 to 5% of visitors will simply be cut off.”

While that sounds like a minor percentage, it extrapolates out to about 37 million people worldwide, with the hardest-hit regions including China, the Middle East, and parts of East Africa — more than 6% of people in China, in fact.

If you’re not a tech wonk, the simplest explanation why is this: the current technology that creates that https (as opposed to http) and the green lock that signals a secure connection on your browser has been deemed outdated and unsafe from cyber attacks. The web is shifting toward an updated version of secure encryption to make your browsing more secure. But sites like CloudFlare and Facebook have suggested the deadline of January 1 for the new encryption is hasty and will discard millions of people who don’t have a choice in their Internet-enabled devices.

In a post responding to the impending changes, Facebook’s Chief Security Officer Alex Stamos expressed the social monolith’s belief in inclusiveness, regardless of outdated web hardware.

“We hope that we can find a way forward that promotes the strongest encryption technologies without leaving behind those who are unable to afford the latest and greatest devices.

TL;DR: you’re probably fine. But now might be a good time to get Great Uncle Frank a stocking stuffer to replace that Sidekick.