That is another OS leak that turned into an official OS. We now have OS 188.8.131.520 which leaked earlier this week turn into an official release by Turkcell. BBNews.pl spotted the new official release and it seems like it is the same.
Warning: This OS will not install on any other BlackBerry besides the one mentioned above. Don’t forget to delete the vendor.xml file located in c:program files>common files>research in motion>apploader to install it on a different carriers device. If you do not know how to upgrade your BlackBerry OS please start by reading this step by step guide.