nih-plug/BREAKING_CHANGES.md

Breaking changes

Since there is no stable release yet, there is also no proper changelog yet. But since not everyone might want to dive through commit messages to find out what's new and what's changed, this document lists all breaking changes in reverse chronological order. If a new feature did not require any changes to existing code then it will not be listed here.

[2022-05-2y]

• The Plugin::initialize() method now takes a &mut impl InitContext instead of a &mut impl ProcessContext.
• Plugin::process() now takes a new aux: &mut AuxiliaryBuffers parameter. This was needed to allow auxiliary (sidechain) inputs and outputs.

[2022-05-22]

• Previously calling param.non_automatable() when constructing a parameter also made the parameter hidden. Hiding a parameter is now done through param.hide(), while param.non_automatable() simply makes it so that the parameter can only be changed manually and not through automation or modulation.
• The current processing mode is now stored in BufferConfig. Previously this could be fetched through a function on the ProcessContext, but this makes more sense as it remains constant until a plugin is deactivated. The BufferConfig now contains a field for the minimum buffer size that may or may not be set depending on the plugin API.

...

Who knows what happened at this point!