Updating or upgrading SongPop will not cause you to lose any of your progress in the game. The only foreseeable way to "lose" progress is due to forgetting your login information and thus being unable to access your account -keeping your username and password somewhere where you can access it is a good idea :)
Remember, your SongPop Username is NOT -
Your Facebook Name (i.e. Jane D.)
Your Game Center Username (Welcome Back Jane D.!)
To see your SongPop Username on a mobile device, go to:
Profile > Settings > Account Info
To see your SongPop Username on Facebook, go to:
Settings (the little gear icon on the right side of the screen) > Profile > Edit
Another thing to remember about your SongPop Username: Usernames are always cAsE sEnSiTiVe so we cannot look you up if you send us a username with inexact capitalization/spaces/characters. It is important that you send us the username exactly as it is displayed in your SongPop Profile Settings.
If you still have any questions about losing your progress, feel free to email email@example.com - We're happy to help!