Getting a new refresh token when using one to get an access token dropbox v2 api - dropbox

Question

In Refresh token is not returned from Dropbox API when using grant_type=refresh_token
The poster asks why he's not getting a new refresh token when using the new dropbox v2 api.
The answer is that it's not needed. Refresh tokens don't expire from dropbox unless revoked.
Is that still the case? I'm reading in https://developers.dropbox.com/oauth-guide
That "When using refresh tokens, your call to the /oauth2/token endpoint with the grant_type of authorization_code will return a new short-lived access token and a new refresh token, which should be securely stored."
But I'm still not seeing a refresh token when I use one to get an access token.
Request:
POST https://api.dropbox.com/oauth2/token HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Host: api.dropbox.com
Content-Length: 363
Expect: 100-continue
Connection: Keep-Alive
refresh_token=<TOKEN>&grant_type=refresh_token&client_id=<ID>&client_secret=<Secret>&scope=account_info.write+account_info.read+files.metadata.write+files.metadata.read+files.content.write+files.content.read+sharing.write+sharing.read+file_requests.write+file_requests.read+contacts.write
Response
HTTP/1.1 200 OK
Cache-Control: no-cache
Content-Type: text/javascript
Date: Thu, 29 Apr 2021 13:30:50 GMT
Pragma: no-cache
Server: envoy
X-Content-Type-Options: nosniff
X-Frame-Options: SAMEORIGIN
X-Server-Response-Time: 35
Vary: Accept-Encoding
X-Dropbox-Response-Origin: far_remote
X-Dropbox-Request-Id: 744233e362ac4b20a00e7a862ae90a16
Content-Length: 395
{"token_type": "bearer", "access_token": "token", "expires_in": 14400, "scope": "account_info.read contacts.write file_requests.read file_requests.write files.content.read files.content.write files.metadata.read files.metadata.write sharing.read sharing.write"}
I'm using the .net api to exchange my refresh token for an access token. But don't see how I'd get the new refresh token back even if it was on the wire. Which it does not appear to be. The refresh tokens themselves don't seem to be expiring when I use them to get access tokens. Will that change in the future?
_DropBoxClient = new DropboxClient(string.Empty, dbap.RefreshToken, sApiKey, sApiSecret, config);
var newScopes = new string[]
{
"account_info.write",
"account_info.read",
"files.metadata.write",
"files.metadata.read",
"files.content.write",
"files.content.read",
"sharing.write",
"sharing.read",
"file_requests.write",
"file_requests.read",
"contacts.write"
};
bool success = Task.Run<bool>(async () => await _DropBoxClient.RefreshAccessToken(newScopes)).Result;

Answer 1

The Dropbox API /oauth2/token endpoint does not return a new refresh token during the refresh process, nor are there plans to make it do so. The official documentation for the Dropbox /oauth2/token endpoint can be found here.
The Dropbox OAuth Guide is referring to when you call /oauth2/token for grant_type=authorization_code, i.e., when first exchanging the authorization code for a short-lived token and (optional) refresh token. (Apologies the "new" there is misleading. We'll fix that up.)
When you call /oauth2/token for grant_type=refresh_token, i.e., when using a refresh token to get a new short-lived access token, it will not return another refresh token.