• -o 4 is now -o 5 and -o 4 is a new intermediate level that shows a subset of the AIS message fields that are relevant for map plotting.
• Experimental switch -go AFC_WIDE on to make the decoder more robust for thermal drift in cheaper RTL-SDR dongles following this discussion. Don't use this unless you have to because of a dongle suffering from thermal drift hampering reception. It will come at a cost of sensitivity. My test database shows 50% improvement in message rate of the default decoder over a standard FM-based decoder, which reduces to 30% with this switch activated. See also the section on Frequency Correction for RTL-SDR dongles.
• The default downsampler uses a simple but efficient CIC5 filter. To mitigate some of the drawbacks of this method, this version now uses by default a simple droop compensator in the form of a fast 3 tap filter which can be switched off with the switch -go DROOP off. More information can be found here
• Includes a first implementation that allows received messages to be posted using the HTTP protocol periodically. Please see this section for more details. This could be an interesting option if you want to submit data to APRS.fi or develop a cloud service for collecting data.