File upload doesn't work on Windows in 4.15.1

[ivan2428i1]

Version

4.15.1

Describe the bug

Same files that used to work perfectly in the Emulator of version 4.14.1, don't get uploaded anymore in 4.15.1 - 400 error code. The bot application's endpoint doesn't even get triggered for such request. Textual messages work fine though.

To Reproduce

Steps to reproduce the behavior:

1. Run Bot Framework Emulator and initiate a conversation with your bot;
2. Click on Attach button to pick a file locally, click "Open" to try to upload it;
3. See error 400 for this POST request

Expected behavior

File should be sent to the bot successfully.

[bug]

[rido-min]

Hi ivan2428i1

Thank you very much for reporting this issue, we can repro in our side.

While we work on the fix, I'm wondering if you can switch back to the previous version.

[fredericomcorda]

Same, may I add that in the 4.15.1 the upload changes the endpoint
from: "directline/conversations/<conversationId>/activities"
to "directline/conversations/<conversationId>/upload"

Couldn't find any doc about this change...

[ivan2428i1]

Rido (@rido-min) Thank you for the response. Yes, I temporary rolled back to 4.14.1, no problem.