OnePlus One gets minor Cyanogen OS update
The OTA ZIP file is 18MB in size, but in order to make it work you will need a stock version of the OS on your phone. In case you want the full ROM experience, the file is 600MB in size and it includes fastboot ZIPs. According to official forums, this Cyanogen OS forums, his update brings about some bug fixes and security updates, possible something like Stagefright. The usual OTA could prove to be failing, but the manual installs are reported as working.
OnePlus One is the only smartphone from the company still running on Cyanogen OS, but the company is working on moving it to its proprietary Oxygen OS as soon as possible. Considering that most OnePlus One users are still using the Cyanogen OS 12 version, this update will bring joy to many. Happy flashing!
Source: OnePlus Forums