We've upgraded our nRF9160 modem firmware and would like to downgrade to the pti_v1.1.x image so that we can test production test commands such as %XMIPIRFFEDBG. Where can we find this image? The production firmware is not listed on the download site: https://www.nordicsemi.com/Products/Development-hardware/nrf9160-dk/download#infotabs
