NRF52840: Cordio Support for Data Length Extension and increasing ATT_MTU for Firmware OTA Updates

We are currently using an IOS App to update the firmware OTA . Since BLE 4.2 support in IOS (IPhone ios) they support DLE Extensions and I was wondering what do we need to ensure that the DLE Extension works in Cordio. We are trying to increase the overall thru’ put of transferring the firmware OTA. We also want to raise the ATT_MTU to 251. Any guidance as to how we can achieve this would be great?

Thanks,
Ajay

@vcoubard any thoughts on this?