Configuration history entries are now one of several typed rows distinguished by change_type — an installment amount change or a contract pricing change — instead of a single flat shape; the fields that were previously always present (changed_at, created_at, entity_id, entity_type, event_id, new_value, org_id, schema_version, source) and the optional context, effective_at, previous_value, source_label, source_reference, and source_system fields are no longer part of the common row, so consumers must read them from the specific row type — affecting GET /v1/billing/billing_accounts/{id}/configuration_history, GET /v1/billing/contracts/{id}/configuration_history, and the pricing information endpoints (breaking)
Contract pricing changes are now tracked in the configuration history: change_type accepts and returns the new contract_pricing_changed value, and a new optional history_change_types query parameter lets several change types be requested at once on all four configuration history and pricing information endpoints
Pricing information (GET /v1/billing/contracts/{id}/pricing_information and GET /v1/billing/billing_accounts/{id}/pricing_information) now returns the full base_prices and working_prices lists of a contract, reports a tariff_type for each base and working price, and accepts a new optional include_history query parameter for returning the configuration history along with it