Token exchange using id_token

i’m trying to implement token exchange using id token but i can’t get it to work.
I filled the request form with following params:

  • client_id
  • client_secret
  • grant_type : urn:ietf:params:oauth:grant-type:token-exchange
  • subject_token: already generated id_token
  • subject_token_type: urn:ietf:params:oauth:token-type:id_token

But i get error: { “error”: “invalid_token”, “error_description”: “Invalid token type, must be access token” }.
Which is kinda weird as i specify the type of token to “id_token”. Is there something i am doing wrong or it is just not possible to refresh tokens by id_token while using keycloak ? But looking at docs this should be possible. Token exchange using access_token does work.
Thanks for answers.

if you look in to src: keycloak/ at bfce612641a70e106b20b136431f0e4046b5c37f · keycloak/keycloak · GitHub

now it only support access token.