Do I need to change the router
How do I improve the WiFi security
MacBook Pro 13″, OS X 10.10
Question marked as
You may be able to change the router settings. Even some new routers have default settings that will trigger Apple's weak security warning. To avoid that warning the router needs to be set to WPA2 AES or to WPA3.
How you change the setting varies by router brand/model. If you don't have instructions, do an internet search for your router or if your router was supplied by your internet provider, check their website.