IFBT4 Firmware Revision History

This model is not capable of firmware updates in the field so no files are available for download. Contact Lectrosonics if you need a firmware update.


IFBT4 v6.3 - 17 December 2018

  • Adjust audio processing to decrease distortion when input is driven deep into limiting. Improvement may not be noticeable in normal operation.

IFBT4 v6.2 - 11 October 2018

Introduces "Nu Hybrid" compat mode, which replaces the legacy "400" mode. "Nu Hybrid" mode conforms to the ETSI standard now in effect for wireless microphone transmitters in the United States. Version 6.x firmware is for use in units shipping with these FCC ID numbers:


All new product shipped after October 13th, 2018 to US customers will bear these FCC ID numbers and use 6.x firmware.

IFBT4 v1.5 - 18 September 2013

Added full frequency block 23 coverage for Australian export models.

IFBT4 v1.4 - 26 September 2008

  • Added external power voltage readout feature and automated warnings if voltage is out of range.
  • TV channel is now correctly reported on blocks 470 and 19.

IFBT4 v1.3 - 22 January 2008

  • Replaced subsonic filter with a quieter one, for a slight improvement in noise performance.
  • Enhanced support for frequency block 944, added support for frequency blocks 470 and 19.

IFBT4 v1.2 - 13 June 2007

Added support for frequency block 944.

IFBT4 v1.1 - 28 March 2007

Made changes to certain factory testing functions for ease of manufacturing. There is no change to features or performance.

IFBT4 v1.0 - 11 January 2007

First production release.