See https://ryanpacini.com/posts/vifileformat/ for a detailed description of the VI FIle Format.

Another resource is https://github.com/tomsoftware/VI-Explorer

LabVIEW 2024 Q1 introduced a new feature, “Develop a project in an older LV version”. The project-level Save Version setting instructs newer LabVIEW versions to save supported project files in a selected older LabVIEW format. This allows a project to be edited in a newer LabVIEW version while remaining maintainable in the configured older version. Unsupported features cannot be saved for the older version.

A prerequisite is that all project items have the “Separate Compiled Code” option enabled.

When migrating a project to a newer LabVIEW version while retaining compatibility with the previous version, prepare the project in the older version first.

1. clear all caches
2. open the project in the older LabVIEW version
3. move all repository dependencies from Dependencies into the appropriate project targets
4. enable Separate compiled code from source file for all project items

   1. the separate compiled code dialog does not include items located under Dependencies!
5. verify that the application runs and builds before opening it in the newer LabVIEW version.
6. configure the project to save for the required older version and verify the application and build again