Microsoft is adding a new security feature in the May 2019 Windows 10 update (also known as update v1903). Windows will warn you if you are connecting to a Wi-Fi hotspot that is using WPA or TKIP encryption. These old encryption methods have long been known to be ineffective and easily bypassed using freely available software from the Internet. As I said in this video from last September, if your home router doesn’t have WPA2 or newer encryption, go get a new router. You are simply not safe. For now, Windows will let you connect, albeit with warning. In the future, look for Microsoft to remove the option to connect to an insecure Wi-Fi hotspot altogether.
For more information on Wi-Fi safety, watch this video.