CODESYS 2.3 was an "OEM" product. Many hardware manufacturers bundled the software with their hardware. You are more likely to find a working copy on a PLC manufacturer's support page than on the CODESYS site.
: The CODESYS Development System is available for free. While the store focuses on V3, legacy versions and converters are often listed under the "Engineering" or "Archive" sections.
To help point you in the right direction for your specific setup, let me know: What are you trying to program?
TwinCAT 2 is heavily based on the CoDeSys 2.3 architecture, though it uses a different interface. System Requirements and OS Compatibility
Are you downloading this for a , or are you looking to use the internal SoftPLC for learning? CODESYS Development System – your programming tool
The search for "CODESYS 2.3.9 download" often comes from engineers and technicians who encounter it in their daily work. The primary reasons for its continued use include:
Before you attempt to install V2.3.9, ensure that your computer meets the necessary specifications. Because this is a 32‑bit application, you will need to run it on a 32‑bit operating system or on a 64‑bit OS that provides 32‑bit compatibility (most Windows versions do). The official minimum and recommended requirements are:
