I connected to our Wi-Fi network and it’s saying weak security

Log into your modem from your computer or phone and change your security setting to AES and it will go away. If you can't, then call your internet company and they will walk you through it.

To add a bit to what the others have provided you, the "trigger" for this warning is specific to WPA wireless security's encryption type. There are two "flavors" of WPA encryption: TKIP & AES. The former is used with WPA; whereas the latter is used by WPA2.

For Apple products, the "WPA/WPA2 Personal" setting would use either TKIP or AES. "WPA2 Personal" would use AES.

If you connect an iPhone to a wireless network that is only using TKIP encryption, you will see this warning.

If you're looking at your Wi-Fi connections in Settings on your iPhone and see an entry labeled “Weak Security,” it means that Apple is warning you that the router you're connected to uses an older, less-secure method of encryption. What you're doing on the Internet can potentially be intercepted by others.

Chances are, your Wi-Fi router is already set to provide the highest security possible, but it would not hurt to check to see if there are other security options that you could use on the product.

If the router is 4-5+ years old it is not capable of providing the latest secure settings for Wi-Fi, so it's probably time to start thinking about a new router.