BTBerryWifi

The Problem:
Your headless Raspberry Pi needs to connect to a new wifi network. You cannot use ssh because your Mac/Pc is on the new network (and the old network is not available). You do not have access to a monitor/keyboard/mouse. Or your RPi is sealed in a box.
The Solution:
The BTBerryWifi app connects to your Headless Raspberry Pi via bluetooth, and allows you to select a wifi network seen by your Raspberry Pi.
A simple familiar interface displays the network SSID (name) , the strength icon , and whether the wifi network is locked (encoded) or open.  
Tap the network to connect. If the network is locked, the app prompts you for the network's password (key).  The Raspberry Pi is now connected!
You can also connect to hidden SSID network . 
Any network you connect to at least once is saved on the raspberry pi for future re-use.
Extra features for supporters:
Encryption to secure network SSID and passwords from bluetooth eavesdropping.
This also locks the Raspberry Pi to only those to whom you give a password so other users with this app cannot connect to your RPi.
Extra information about the RPi: 
- IP4, IP6 addresses on the wifi network.
- Mac address of the ethernet, wifi and bluetooth adapters.
- Detail strength (dbM) and channel/frequency of all networks around the pi. (great for handling interference!)
- user defined info from the RPi displayed on the iPhone/iPad

Notes: 
1) IMPORTANT: 
You must FISRT install the corresponding python program on the Raspberry Pi in order for the Raspberry Pi to communicate with the iPhone app.The python code to be installed is available for free (open source). 
An installation script is provided: follow the instructions at https://normfrenette.com/Set-wifi-via-bluetooth/Installation-RaspberryPi-automatic/ or https://github.com/nksan/Rpi-SetWiFi-viaBluetooth
2) Tested on Raspberry Pi 3B+,4 and 5 (OS: Buster(10), Bullseye(11), Bookworm(12), Ubuntu) & Banana pi (Armbian).
3) The app user guide can be found at: https://normfrenette.com/Set-wifi-via-bluetooth/iPhone-App-iPhone-app-usage/
4) there are also demo/user guides videos:
- setting the wifi network (various options): https://www.youtube.com/watch?v=Lt_nxcghhZE
- using "supporter" features: https://www.youtube.com/watch?v=x-VTXTclnhw