Is there any thing to do with App service or azure bot price tier upgrade? will it allow attachment above 4mb size to upload. Currently when uploading any attachment above 4mb size, the attachment is getting timeout issue and not reaching to Bot only. In Bot Emulator there is not attachment size issue, but when it published to app service , attachments above 4mb are getting failed.
It looks like the 4MB limit is enforced by the Direct Line API (by design) and cannot be configured. It is not related to your Azure pricing tier.
It makes sense that it would work in the emulator, since you're testing locally and not hitting the API.
You would need to work around this limitation by either downsizing files where appropriate, or by disallowing uploads greater than 4MB.
Sources: