CNET:

This year, amid the flurry of new features and performance claims, Apple made a pretty interesting technical announcement. No, there’s no support for 5G with any of the new models (we expect that’ll come in 2020), but that doesn’t mean there won’t be speed. All three of them — the iPhone 11, the iPhone 11 Pro, and the iPhone 11 Pro Max — include support for Wi-Fi 6.

Basically, it’s “future proofing” your iPhone 11 devices.