Version 2.1.0

• Narrowband FM demodulation support
• Automatic Frequency Control
• Append mode for recording (enabled by default)
• Dongles, channels and outputs can be individually enabled and disabled
  by a simple config flag (no need to comment out or delete large
  configuration sections)
• Use VBR for MP3 encoding
• Modified power level calculation algorithm (better sensitivity)
• Support for manual squelch setting
• Bug fixes