# Model 552 Changelog

NOTE, when updating between versions where any digit but the last has changed:
- New settings have been added
- The update will set reset the unit to Factory Default settings, except for IP settings
- Previous settings will automatically be recalled after Factory Defaults are loaded
- This will take ~30 seconds after the unit has been updated, and it will reboot after
- Any new settings that didn't exist in the previous firmware will be at their respective defaults

How to update firmware:
- Access the Admin webpage
- Click "Select Firmware File..."
- Select the firmware (.bin file)
- Click "Update Firmware"
- Wait for update to complete

## [1.3.1.3] - 2026-07-22

### Fixed
- Fixed the HD PSD fields not being cleared when changing from a non-empty PSD to an empty PSD

## [1.3.1.2] - 2026-07-02

### Changed
- This has 551 specific fixes. Updated 552 to maintain parity with 551.

## [1.3.1.1] - 2025-09-02

### Changed
- Internal change for factory checkout procedure

## [1.3.1.0] - 2025-08-13

### Added
- Interface for controlling DTAC on GatesAir FMXi 4g: updates delay to keep FM and HD1 aligned

### Fixed
- Allow Dante gateway and DNS to be set to 0.0.0.0
- This update should address some occurrences of the display becoming "glitchy"

## [1.3.0.12] - 2024-11-13

### Fixed
- Consistent audio metering below -40dB (between 541/551/552/526)

## [1.3.0.11] - 2024-10-18

### Fixed
- Fixed the Overmod and FM Audio Loss GPOs being swapped

## [1.3.0.10] - 2024-07-30

### Fixed
- Fixed not being able to set the last GPO via the Setup webpage
- Fixed the possibility of the firmware upload process failing, requiring a reboot to try again.
  Since this fixes that, it may take several tries to get this firmware to upload successfully.

## [1.3.0.9] - 2024-04-30

### Fixed
- Fixed the web audio stream not working anymore after latest iOS update

## [1.3.0.8] - 2024-03-29

### Added
- FSK ID alarm
- Carrier offset measurement

## [1.3.0.7] - 2024-01-29

### Fixed
- Internal change for checkout procedure

## [1.3.0.6] - 2023-12-12

### Added
- HD diagnostics to MIB (SNMP)

### Fixed
- SNMP/MIB: fix overmod and FM audio loss traps being swapped
- Fix SCA settings not being applied when loading a preset
- Fix FM/HD1 delay measurement being off by a few samples when the delay is large

## [1.3.0.5] - 2023-08-29

### Added
- NTP server sync status is now shown on the Time webpage

### Fixed
- Fixed FM/HD1 alignment off by 5 samples (showed up in 1.3.0.4)
- Fixed presets with double quotes (") in the name messing up the alarm log
- Fixed 552 MIB typo causing parsing problems

## [1.3.0.4] - 2023-08-02

### Fixed
- Fix possibility of HD1 audio slipping by 2048 samples under certain conditions.
  NOTE: this fix requires updating the HD Radio decoders in the 552. The update
  will take an additional minute or so as a result.
- Fixed some low level distortion in the MPX output
- Fixed "dBuV" label on the Now Playing webpage showing as "dB&mu;V"

### Changed
- Metering response has been updated to match the 541, which is designed to more
  closely match that of the 531. This results in more realistic peak metering.

## [1.3.0.3] - 2023-05-24

### Fixed
- Fixed the Overmod and FM Audio Loss email notifications being swapped

## [1.3.0.1] - 2023-04-06

### Fixed
- Fixed multipath on Now Playing webpage and SNMP showing 10x the actual value
- Listener Experience webpage: fixed the wrong (older) image being indicated as the current image if it appears multiple times in the image history
- Fix Artist Experience images not updating for a while after a partial/incomplete image is received

## [1.3.0.0] - 2023-01-26
NOTE TO SNMP USERS: make sure to use the new MIB file, as new features means new OIDs.
Download it from the SNMP webpage after updating to this new firmware.

### Added
- SCA tuner for measuring injection level of a SCA
- "RDS Clock Time out of range" alarm
- "RDS TMC not received" alarm
- "HD TMC not received" alarm
- "SCA loss" alarm
- "Multipath" alarm
- Ability to control which presets are included in StationRotation
- Split mode (FM/HD1) audio spectrum

### Changed
- Make order of alarms consistent everywhere

### Fixed
- Fixed Dante/AoIP output levels loading the Digital output levels on boot
- Fixed loudness window measuring over 1/10th the set window size (120 seconds was actually 12 seconds, etc.)

## [1.0.1.13] - 2022-07-21
### Added
- Placeholder/example text in SMTP fields on Email webpage, for clarity

### Fixed
- Fix being able to load a preset that doesn't exist
- Fixed status bytes CRC not being correct for assignable AES output which caused some very specific devices to reject the audio

## [1.0.1.12] - 2022-04-11
### Changed
- Boot time decreased by ~2 seconds

### Fixed
- Separation and Crosstalk meters were not showing correct values
- Assignable digital output source selector in GUI popup (pressing "headphones" icon) set the analog output source
- Headphones output would clip if audio levels >3dB
