Changes introduced in 3.00 include:

New

For all models:

• USB control from the Korg NanoKontrol Studio, Korg NanoKontrol2, Akai MidiMix, and Novation Launch Control XL USB control surfaces. Other USB control surfaces are not supported. Includes support for fader, trim, pan, low cut, reverb, solo, mute, track arm, monitor, transport control, LR output level, and user-programmable shortcut buttons.
  Note: available features depend on the control surface being used and whether Audio or Music projects are enabled. For more information, see the USB Controller chapter in your MixPre User Guide.*

For MixPre-3, -6, and -10T only:

• Pre-roll: saves up to 10 seconds of audio before the "record" button is pressed. Select up to 10 seconds of pre-roll on the MixPre-10T and 5 seconds of pre-roll on the MixPre-3 & -6. Pre-roll time is reduced at 96 kHz and higher sampling rates.

For MixPre-3 and 3M only:

• Phase invert option now available for the MixPre-3. Phase invert is already available for all other MixPre models.

For MixPre-6 and -10T only:

• Ambisonics and binaural recording/monitoring (-6 and -10T Audio projects only). Requires installation of the free Ambisonics Plugin available at the Sound Devices Plugin Store.

For all M models and Music projects on models with Musician Plugin:

• Bluetooth LE wireless remote control using the Android or iOS Wingman app. Includes 12-track monitoring, mix metering, transport control, time counter, track naming and arming.
• Support for the new Windows ASIO driver, v2.9.92.1. This enables a MixPre running a Music project to be used as a multichannel USB audio interface with Windows computers. This ASIO driver is required when using the MixPre-3M, -6M, or -10M or when running Music projects in the MixPre-3, -6, or -10T.

Changed

For all models:

• Meter scale now included on Channel screen meter.

Fixed

For all models:

• Noise that occurred when playing back MixPre-recorded 96 kHz or 192 kHz files at a fraction of their normal speed has been eliminated.
• The UI no longer occasionally switches to a Channel screen's first page after selecting a linking option.
• Fader or gain levels now only display at the top of the Home screen when being adjusted.
• Improved handling of projects without an SD card connected.
• Rare event where USB audio inputs 3 and 4 were routed directly to the LR tracks has been resolved.
• Files with both Mix and ISO tracks now consistently import correctly.
• Imported files now consistently playback at correct speed.
• Ticking noises that occasionally occurred when playing back imported files containing cue markers have been removed.
• Sample rate stays consistent between the MixPre and a computer when changing projects without an SD card inserted.
• LR gain now remains correct after loading a preset with L and R unlinked and set to different gain values.
• When transitioning between playback and stop, solo'd track remains consistent.
• All channels of a linked group can be solo'd in the headphone output.
• Improved USB-A port connectivity.

For MixPre-3, -6, and -10T only:

• Playback meters now display in Audio projects when meters are set to Off.
• Custom Mode with Gain set to Basic and Headphones set to Advanced now allows deselecting of all sources in the Headphone Preset matrix.
• Live audio now returns consistently after playback when device is connected via USB to a computer.

For all M models and Music projects on models with Musician Plugin:

• The maximum number of cue markers in Music projects has been increased to 99.
• All tracks are now present after importing non-native files into Music projects.
• Imported non-native content does not disappear after overdubbing.
• A lockup no longer occurs if the HP encoder is pressed when viewing an empty History list.

For MixPre-3 and -6 models only:

• A lockup that occasionally occurred when switching from a battery source to a low USB power source has been resolved.

For MixPre-6 and -10T models only:

• Linking settings remain correct when switching between Music and Audio projects.
• Live audio for channels 9 & 10 (on MixPre-10T) and channels 5 & 6 (on MixPre-6) return after playback.

For MixPre-10T only:

• Timecode generator reset warning no longer appears when booting up in Music projects.
• Record Trigger setting is now stored across power cycles.

For MixPre-10T and -10M only:

• In Stop mode, navigation no longer skips between cue marks (on MixPre-10M or in Music projects on the MixPre-10T).

https://www.sounddevices.com/support/downloads/mixpres-firmware/