Detectivereview let us know that OS 18.104.22.1688 has made its way online for the BlackBerry Curve 8520 thanks to the upstanding folk @CrackBerry. It may take a few reloads to get it working but it does in the end.
NOTE: Do not install this software if you do not know what you are doing. It may make your BlackBerry FUBAR or just plain angry.
Keep the tips coming!