Weak Security

This may be weak security of your WiFi connection.

Consider more secure wifi configuration.

Change your router’s WiFi to use WPA2-AES (CCMP) with no WPA or TKIP. Updating this setting ensures that your devices always connect in one encryption mode

1. TKIP is obsolete and not considered secure. Choose WPA2, the latest encryption standard, with AES encryption for optimal security
2. If your router doesn’t specify TKIP or AES, the WPA2 option probably uses AES

Check your WiFi Router / Modem for --> Recommended settings for Wi-Fi routers and access points ...

The installer is incorrect.

WPA2 configured securely should not trigger that message. Insecurely-configured networks and insecurely-configured extenders do.

Security

WPA3 Personal for better security, or WPA2/WPA3 Transitional for compatibility with older devices

The security setting defines the type of authentication and encryption used by your router, and the level of privacy protection for data transmitted over its network. Whichever level of security you choose, always set a strong password for joining the network.

• WPA3 Personal is the newest, most secure protocol currently available for Wi-Fi devices. It works with all devices that support Wi-Fi 6 (802.11ax), and some older devices. 
• WPA2/WPA3 Transitional is a mixed mode that uses WPA3 Personal with devices that support that protocol, while allowing older devices to use WPA2 Personal (AES) instead.
• WPA2 Personal (AES) is appropriate when you can't use one of the more secure modes. In that case, also choose AES as the encryption or cipher type, if available.

Settings that turn off security, such as None, Open, or Unsecured, are strongly discouraged. Turning off security disables authentication and encryption and allows anyone to join your network, access its shared resources (including printers, computers, and smart devices), use your internet connection, and monitor data transmitted over your network or internet connection (including the websites you visit). This is a risk even if security is turned off temporarily or for a guest network.

Don't create or join networks that use older, deprecated security protocols like WPA/WPA2 Mixed Mode, WPA Personal, TKIP, Dynamic WEP (WEP with 802.1X), WEP Transitional Security Network, WEP Open, or WEP Shared. These are no longer secure, and they reduce network reliability and performance. Apple devices show a security warning when joining such networks.

It would be better if you can please re-post with a screenshot, in order to understand the phenomenon better. Images / pictures speak louder than words. (Do not provide any personal credentials, such as email id, apple id, IMEI number, Serial Number, Phone number, Order ID, if you are sharing a map ensure your location is not identifiable. etc)

Consider this explanation / advice offered by my professional network designer / installer:

”Quick answer. Ignore the message. 

Apple is pushing an upgrade out that is already receiving a lot of pushback from people as the new security settings are geared toward Wi-Fi6 deployment. The problem with Wi-Fi6 is that ALL devices must be Wi-Fi6 compatible for it to work as designed. This includes printer, TVs, thermostats, etc. Unless you are starting to build out a new network from scratch Wi-Fi6 is not a viable implementation for at least a couple of years as most folks are not ready to throw out brand new devices to make it work. (Example, that new TV you just got in the kitchen is not Wi-Fi6 compatible) Business applications usually do a wholesale switch of equipment so they can implement Wi-Fi6 easier than in the residential world.

You are currently running WPA/WPA2 encryption on your network. That is why you are seeing the message. This is a very solid encryption that I have no worries about. I expect Apple to adjust they message in the near future.”