Came here to say this. From the top-level readme @ https://github.com/intersystems/ipm:
IPM 0.9.0+ can be installed with different versions and registry settings per namespace, and does not have the community package registry enabled by default. If you want the legacy (<=0.7.x) behavior of a system-wide installation and access to community packages in all namespaces, run zpm "enable -community" after installing IPM. See zpm "help enable" for details.
Found the answer:
class Foo.Baz extends Foo.Bar
{
Parameter SETTINGS = "-Whatever";
}
Thought I'd seen that syntax once, but was looking at a class further down the hierarchy and also needed to recompile it to have the change in the intermediate class take effect.
This query was helpful to identify settings behavior in built-in interop classes:
select parent,_default from %Dictionary.ParameterDefinition where name = 'SETTINGS'
Thanks! I couldn't actually find that in the docs (just wasn't searching correctly, I guess).