How to use backchannel log out for Single log out

Hello ,
I have 3 clients running under the same realm. When the main client is logged out i want the other 2 to get logged out as well.
The clients are running on :
http://localhost:8080 (java servlet application using tomcat filters)

keycloak is running http:localhost:8180

I can log out from the main application (localhost:8080) using HttpServletRequest.logout(); and it works fine but it won’t log me out from :3000 and :4000.

Backchannel logout is supported only from recent Keycloak 12.x. Of course OIDC clients must be configured for that and it must be supported in your apps.