Does the RN4870 Bluetooth® module support the Data Length Extension (DLE) feature?
The RN4870, rev 1.28, partially supports Data Length Extension (DLE). The normal data payload size in BLE without DLE is 20 bytes. With the DLE feature enabled, the data payload size should be 251 bytes. However, in RN4870 rev 1.28, the size is 151 bytes. It is not a full implementation of the DLE.
The DLE feature is embedded into the lower levels of the Bluetooth® stack and there are no specific commands to enable or disable DLE. Essentially, if the peer device also supports DLE, then the DLE feature will be enabled (i.e., there are no specific commands that you need to send to the module to increase throughput using DLE).