It is possible to program Mitsubishi PLC using GX Developer.
"GX Developer supports all MELSEC controllers from the compact PLCs of the MELSEC FX series to the modular PLCs including MELSEC System Q. This software shines with a simple, intuitive interface and a short learning curve. GX Developer supports the MELSEC instruction list (IL), MELSEC ladder diagram (LD) and MELSEC sequential function chart languages. You can switch back and forth between IL and LD at will while you are working. You can program your own function blocks (MELSEC QnA/QnAS/System Q series), and a wide range of utilities are available for configuring special function modules for the MELSEC System Q."