Looks like RIM is still showing some love for the older Curve series. The BlackBerry Curve 8520 official OS version 188.8.131.521 has been released from Orange Austria. Its been a long time since we have seen an official release for this device so if you have one get out that USB cord and give your device a fresh new OS. As always please be sure to let us know your findings/fixes.
The Software Platform and Applications version numbers can be found under Options-About screen on the handheld.