https://arstechnica.com/gadgets/2017/10/apple-releases-watchos-4-0-1-with-fix-for-series-3-ltewi-fi-bug/

Apple released a software update for its Series 3 watches today that will upgrade watchOS 4 to watchOS 4.0.1. This is the first software update to watchOS 4 since it became available for all Apple Watch models on September 19. The watchOS 4.0.1 update focuses on fixing a peculiar Wi-Fi issue some Series 3 with LTE models experienced. That issue prevented the devices from connecting to LTE in favor of connecting to an inaccessible but familiar Wi-Fi network.