Hey Thomas, thanks for bringing this up. I believe there is room for improvement in our official documentation on the topic of upgrading the DQMH framework vs. upgrading DQMH modules.
DQMH is designed with backward compatibility in mind: Old modules can continue to function inside projects that use newer DQMH scripting tools. You can mix modules created with different DQMH versions in the same project. However, if you want to use new features (e.g., improved error handling, updated broadcast patterns, new helper VIs), you need to manually update each module using the provided tools.
Upgrading the framework
Upgrading the DQMH framework itself from one release to the next is generally a well-structured and non-destructive process—but it's important to understand what changes, what doesn't, and how it impacts your existing code:
- The DQMH framework consists of a number of classes and libraries, a set of project templates and scripting tools (DQMH scripting) installed globally (mostly into vi.lib).
- DQMH modules are copied into your project at the time of creation and do not live in vi.lib. They do make use of a number of VIs installed into vi.lib (namely the module admin lvclass and the message queue lvclass) which are 100% backwards compatible and never introduce any breaking changes in the first place.
This design has important implications for versioning and upgrades: Upgrading the framework only involves installing the new version of the DQMH framework via VI Package Manager.
Existing modules remain unchanged after a framework upgrade. They contain snapshots of the template elements that were current at the time of creation. These modules continue to work because they are self-contained for the most part and they don’t depend on any global shared code that should ever change in between versions. On the downside, they also do not automatically adopt new features or fixes introduced in the latest DQMH version.
Upgrading existing modules
To benefit from the new framework features, you should upgrade your existing DQMH modules. You should use the "Validate Module" feature to check your modules for compatibility with the installed version of the DQMH framework.
The Validation Tool will detect and list all the places where existing modules (ones that were created with an older version of DQMH) differ from what a module created in the latest version would look like. Most of these places can be fixed automatically just with the click of the button. The Fixer Tool will tell you exactly what it does and how it's modifying code. Some parts of your modules - mostly those places that contain manually written code - will still need your manual decision-making, though.
Recommendations:
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Upgrade to the latest version of the framework if possible
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Use the Validate and Update tools in the Tools menu to upgrade your existing code
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Always employ source code control to have a fallback - some scripting operations are hard to undo otherwise
Let me know if this clarifies things, and what might still be unclear.
(edited for clarity)
