CoDeSys achieved massive popularity because it fully standardizes PLC programming under the international standard. Version 2.3.9 includes all five standard programming languages in a single, lightweight package:
While CODESYS V2.3.9 is no longer available on the official website, it remains a crucial tool for maintaining legacy industrial machines. The key is to source the package from your hardware vendor (like WAGO or ifm) and run it in a stable, older Windows environment, ideally via a virtual machine. However, as CODESYS V3 offers substantial technical advantages, users should use this opportunity to plan for a gradual transition of their existing projects to the modern platform whenever possible. codesys 2.3.9 download
Right-click the .exe file and select "Run as Administrator" to ensure registry entries are created correctly. older Windows environment