Airspy has announced the latest releases of SDR# r1702, libairspyhf r1.5.0 and Airspy HF+ Firmware r2.4.0.
Here's a summary of the changes:
The FM Stereo flag was added in the SDR# API: FmPilotIsDetected.
A new experimental Low-IF mode at a lower sample rate (256ksps IQ) was added across the chain to allow portable devices to operate smoothly without requiring further DC/IQ correction or frequency translation. This mode is considered "experimental" because the AGC has yet to be optimized to accommodate for the smaller bandwidth, but it is already usable as-is with the AGC always on.
For the curious types, 256ksps Low-IF was obtained by shifting the IF, adding a narrower channel filter and decimating 768ksps by 3. This gives a wonderful number that is a multiple of a known sound card standard rate: 32kHz.
The IQ streaming and command handling were optimized to allow all of this processing to happen. A positive side effect is that the streaming is no longer interrupted by the commands (set frequency, gain, etc.) - and this one is not experimental.
SDR# r1.0.0.1702 : https://airspy.com/download
libairspyhf r1.5.0: https://github.com/airspy/airspyhf/tree/master
HF+ Firmware R2.0.4 : https://airspy.com/downloads/airspy-hf-flash-20190708-bb.zip