MSX computers are emulated on many platforms today. Early MSX emulators were often based on the code of the pioneer fMSX, a portable MSX emulator by Marat Fayzullin. Many emulators removed Fayzullin's Z80 emulation code entirely in later versions to avoid legal problems, as at the time fMSX wasn't free software. Somewhat later fMSX source code became free for non-profit use; however a license was still required for commercial use. On December 31 2013, the Windows version of fMSX 3.7 was released, free for anyone to use.