I believe what is happening is that iOS as of version 10 has started warning users that WEP should no longer be used. It's likely that the iOS version you had before the update did not have such a warning. So, nothing may have changed with your WiFi, it's just that your iPad is doing you a favor and alerting you that you should improve the security on your Wireless router.
Here are a few tips and a possible solution.
- NEVER ignore a browser indicator of an insecure website that you know should be secure (like a banking site). This, however, is likely unrelated to your WiFi problem. Work on this as a separate issue. No technical support professional should ever tell you to ignore this in your browser.
- The WEP standard is very old, insecure, and should no longer be used
- Any router that is still set to use WEP is certainly old and should may need to be replaced with a newer, more secure, and faster router.
- Before replacing your router, instead, try logging into it's interface and changing your WiFi security protocol to WPA2 (will require setting a strong new passphrase). While you are at it, change the name of your Wireless network so your existing devices do not try to join the network with the old WEP password. If your router does not have an option for WPA2 security, then it's time for a new router.
- If you were able to change your router to use WPA2, then try joining the new network with your iPad. Hopefully the warning will no longer be displayed.
- If you could not set your router to use WPA2, then buy a new one that says 802.11ac on the box. I would recommend AirPort Express or AirPort Extreme from Apple (Networking - Mac Accessories - Apple)
