Today, a Linux P2000 (FLEX 1600) decoder has been announced on
https://github.com/jbrunink/p2000scanner. It is partly based on the PDW source.
'
P2000scanner is CLI-based *nix application written in C. It uses RS232 to communicate with a receiver (confirmed to work with Flexbox and FTDI-based RS232-USB converter). It can be used in several modes, it can decode all the received information and just present that, it can write all the decoded information to a file (JSON-formatted) and/or send it with ZMQ (pubsub implementation) to subscribers (also JSON-formatted).
At the moment p2000scanner only supports 1600-bit/2-FSK FLEX. (used in the Netherlands)'