Interactive Brokers clarifies stance on stop orders
For attached stop orders, including the stop loss portion of an attached bracket order, the order type on the TWS platform will default to the stop order type, being either stop or stop limit, that is natively supported.

Last week, FinanceFeeds reported that prominent North American electronic brokerage Interactive Brokers had made a revision to its proprietary TWS platform to choose native over simulated Stop and Stop Limit Orders.
The company had announced that, for attached orders that offer both the Stop and Stop Limit order types, if traders choose an order type that is simulated, and the routing exchange offers the other natively, TWS will use the order type that is native.
Following that, Interactive Brokers has revised its position, concluding that for attached stop orders, including the stop loss portion of an attached bracket order, the order type on the TWS platform will default to the stop order type, being either stop or stop limit, that is natively supported.
Interactive Brokers further reiterates that prior to submitting the order, traders can change the order type to a non-native stop type. They are not forced into native order.
The rationale behind this is to clarify the company’s actual final position on this matter.