Discovered Lumiya was not on Android Play Store today when I was populating a new phone with app. Here is the solution I used .
1) get the APK Extractor app on your old phone.
2) Make a bluetooth connection from old phone to new
3) Run APK Extractor -- click on the 3 dots on Lumiya from the list of all your apps that will be displayed
4) Select share and then bluetooth. You will need to look for a notice on the new phone to accept the transfer.
5) Once transferred open the lumiya install file with the app installer. If you don't get a prompt for what action to take w