CLOSED: ZHA: Namron OTA Upgrade

I need to upgrade firmware of my Namrom-switches. I have downloaded new firmware from the vendor and followed ZHA OTA Firmware Update / Upgrade

Unfortunately it fails with following log-entry:

2023-03-23 12:57:12.550 DEBUG (MainThread) [zigpy.zcl] [0x26E5:1:0x0019] OTA query_next_image handler for ‘NAMRON AS 4512719’: field_control=FieldControl.HardwareVersion, manufacturer_id=4644, image_type=1000, current_file_version=20, hardware_version=632, model=‘4512719’
2023-03-23 12:57:12.554 DEBUG (MainThread) [zigpy.zcl] [0x26E5:1:0x0019] No OTA image is available

Where should I start?

Seems like there are no upgrade available.