Unlike v20.03, opening and saving a project in v20.04 does not force it to become incompatible with older versions.
For years, Rockwell Automation maintained minor revision compatibility within major releases. This changed with version 20.03, which introduced "enhanced resiliency" and security features that made it incompatible with 20.01. Rslogix 5000 Version 20.04 Download
Version 20.04 allows a single workstation to open, upload, and go online with projects from both 20.01 and 20.03 . Unlike v20