Please make sure this stays backward compatible. Changing APIs from a single OpfActiveConfiguration to OpfActiveConfiguration[] (and similar signature changes like activeConfiguration → activeConfigurations) is a breaking change for existing consumers.

We’d like this to be strictly backward compatible and preserve the exact old behavior when a single OpfActiveConfiguration is provided. Only when an array is passed should we execute the new multi-config logic.

Concretely, please add explicit branching everywhere the new logic is used, e.g.:

@Input() activeConfiguration: OpfActiveConfiguration | OpfActiveConfiguration[];
if (Array.isArray(this.activeConfiguration)) {
  // here TS knows: OpfActiveConfiguration[]
  // run NEW multi-config logic
} else {
  // here TS knows: OpfActiveConfiguration
  // keep OLD single-config logic
}

Same principle for any helpers/services that changed from activeConfiguration → activeConfigurations: keep the old single-config path intact, and only use the new code when an array is actually provided.