Correct use of files.getUploadURLExternal in Curl command line

I was using:

Slack’s file.upload will get deprecated. What to use instead?

I was using:

Slack’s file.upload will get deprecated. What to use instead?

I was using:

Slack’s file.upload will get deprecated. What to use instead?

I was using:

Slack’s file.upload will get deprecated. What to use instead?

I was using:

Slack’s file.upload will get deprecated. What to use instead?

I was using:

Slack’s file.upload will get deprecated. What to use instead?

I was using:

Slack’s file.upload will get deprecated. What to use instead?

I was using:

Get a list of slack channels that a given user have posting rights to

The conversations.list Slack API returns all the channels that a user can visit. However, how can I get list of channels that a given user has posting access to ?

How to configure a Slack App so that with OAuth it hands back data to a Windows Desktop application?

I manage a C# / .NET Windows Application (Winforms). For several years, we’ve had this application rigged up so that users could press a single button to create an MS Teams meeting. This was done via Azure Portal, where an “application registration” had been set up for our application… and configured properly to handle the authorization.