IPluginCompatibility for u-he plugins within FL Studio 25

[MrJubbly]

Feature: VST2 > VST3 migration support for hosts using the IPluginCompatibility interface.

I am currently testing the implementation of IPluginCompatibility for u-he plugins within FL Studio 25.1.0.4868, which has just been released. (on Windows 11 23H2 - Build 22631.5472)

1. I am testing this feature by creating a new empty Project and then loading VST2 instances of all my available u-he plugins and then saving the Project.

2. Next I move all the VST2 .dll files for u-he plugins from their installation folder to another location (e.g. "Desktop"), to render them inaccessible to the DAW.

3. Then I try reloading the Test Project, to see which plugins will automatically migrate to their VST3 equivalent plugins, when the VST2 formats are unavailable.

So far, the results are a bit hit and miss. So I want to query this with u-he before reporting back to Image-Line, on hopefully fixing the issues.

The list of u-he VST plugins which DO successfully migrate to VST3 includes the following:

• Diva, Hive, TyrellN6, ZebraHZ, Presswerk, Satin, Twangstrom.

The list of u-he VST plugins which DO NOT migrate to VST3 includes the following:

• FilterscapeVA, Repro-1, Repro-5, Zebra2, Zebralette, Protoverb, Zebrify, ZRev, Filterscape, FilterscapeQ6

I believe all these plugins are the most recent up-to-date official releases available from the u-he website.

Can anybody from u-he make sense of why some of those above-named plugins should automatically migrate from VST2 > VST3, while the others do not?

Is there something different about how migration has been implemented within each group of the plugins above, which might explain the issue, or assist with my bug report to Image-Line?

Any advice or assistance you could provide would be appreciated.

Thank you.

[Urs]

So, hmmm, sounds like maybe they need to add support for VST3 binaries which contain multiple plug-ins.

In our case, e.g. Zebra2.vst3 contains plug-in migration data for 3 separate VST2 plug-ins (Zebra2.dll, Zebrify.dll, ZRev.dll). Likewise, Repro1.vst3 includes such data for 2 plug-ins and Filterscape for 3.

While this isn't a super common thing in plug-in land, I'm pretty sure we're not the only developers who do this, and doing so is well within the VST3 specifications (just like it is in the specs for AAX, AU and CLAP).

(I feel a bit like a guinea pig which has been thrown into the water to see if it can swim, and at the same time I feel like we're doing the work that Steinberg should have been doing, like testing and certifying hosts for VST3 compatibility)

That said, it's quite likely that Protoverb does not yet have the latest IPluginCompatibility layer.

[tasmaniandevil]

What Urs said.
Our freeware plugins (all apart from Zebralette2) first need to be updated to include IPluginCompatibility. That's why Protoverb migration does not work yet.

[MrJubbly]

Thank you for your feedback.

I will include this within my bug report to Image-Line to hopefully assist them in remedying the issue.

[Urs]

They can always contact us directly, I'm sure they have our details.