PPSSPP is an open source project, licensed under the GPL 2.0 (or later). Anyone is welcome to contribute improvements to the code. Partly thanks to such contributions, PPSSPP's compatibility is steadily increasing, letting us all play our PSP games on the devices of our choice.

November 30, 2017: PPSSPP 1.5.2, - fixes for common crashes
Released a quick update to take care of some common crashes in 1.5.



November 29, 2017: PPSSPP 1.5 - Vulkan is here!
1.5 has support for Vulkan, the new faster way to draw graphics. Supported on many modern Android devices, and if enabled (change Backend in Graphics settings) you will see a massive speed boost. PPSSPP 1.5 also has the usual assortment of fixes:

Full Vulkan support, also for Android now. Very fast on supported devices. (#10033, #10049)
Smarter graphics state management, reduced CPU consumption on all backends (#9899)
Android: Support for Arabic and other scripts we couldn't support before
Fix Android widgets, screen scaling (#10145)
Fixes to video dumping
Geometry problems fixed in Medal of Honor
Implement immediate draws, fixing Thrillville (#7459)
Software rendering improvements, speed and accuracy
Hardware tesselation of PSP Beziers and Splines (used by a few games)
Partial sceUsbGps and sceUsbCam support (Android)
Android "Sustained performance mode" to avoid thermal throttling (#9901)
Linux controller mapping fixes (#9997)
Assorted bugfixes and compatibility improvements
Note that Google Play might take a day or two to update, I'm doing a slow rollout this time to catch unexpected crashes from the new Vulkan backend etc. Some issues have been found already, fixes will be made.
For Windows, Android, Linux, and macOS

http://www.ppsspp.org