VST3 not recognized in existing Session after updating from JUCE 6.0.1 to current develop tip

After updating a CMake based Plugin project I hadn’t touched for some months from JUCE 6.0.1 to the current develop tip the VST3 isn’t recognized as the same plugin in an existing Reaper session anymore. This happens without touching the CMakeLists at all or doing any meaningful changes to the code.

Now before I start bisecting, does that sound familiar to anyone? Besides that, since I guess something regarding the plugin description will be the cause, is there any host application that displays all the details a plugin reports to the host to be able to debug what could make Reaper assume that the plugin is no longer the same one?

Stab in the dark - did you see this?

I don’t think it’s related. First of all, what I experience only affects VST3, the AU version is recognized as the same before and after the JUCE update. Then I didn’t touch the version in CMake number and the version number is 0.9.7 – so as far as I can see not related with the kind of problems reported in that topic.

Just stepped through the master release versions and could narrow the problem down to somewhere between 6.0.4 and 6.0.5. I inspected BREAKING-CHANGES.txt and found

A typo in the JUCEUtils CMake script that caused the wrong manufacturer code to
be set in the compile definitions for a plugin was fixed.

Possible Issues
The manufacturer code for plugins built under CMake with this version of JUCE
will differ from the manufacturer code that was generated previously.

If you have released plugins that used the old, incorrect manufacturer code and
wish to continue using this code for backwards compatibility, add the following
to your `juce_add_plugin` call:


In most cases, this should not be necessary, and we recommend using the fixed

And indeed USE_LEGACY_COMPATIBILITY_PLUGIN_CODE TRUE makes my plugin re-appear again. Seems like it was just released at a bad timepoint. However, I didn’t find a forum topic where the details of this change are discussed – who knows more about that change?

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