Hello @Petr Maslak ,
Messages sent from (azure iot edge) devices to the cloud using an IoT Hub are limited to the size of 256KB. These messages are measured in 4KB parts to check the daily consumption limits.
There are multiple ways to send C2D messages with different limitations:
- Direct methods, max size 128KB
- desired properties, max size 32KB (shared with other logic; it's not advertised for large chunks of information)
- cloud-to-device messages, max size 64KB
So, you are able to send larger messages.
Check the pros and cons of all three ways, before you decide what to do.
This functionality is specialized in secure device registration and D2C / C2D messaging. If you wish to send actual files from the cloud to the edge, you have to bring your own logic implementation.