20.12 | Rslogix 5000 Firmware

Revision 20.12/20.012 is noted for improved interaction with later software versions like v20.04, which was designed to resolve minor revision compatibility "lock-out" issues seen in v20.03. Update Precautions

you have existing v20 projects and need the bug fixes or hardware support (e.g., newer EN2T series D). Otherwise stay on 20.011 (if stable) or upgrade to Studio 5000 v32+ for new development. rslogix 5000 firmware 20.12