Hello,

I currently encounter an issue with the Principal check in TransportHandlingSockJsService (Spring Boot 3.5.9 / spring-websocket 6.2.15).
in my case the Principal is a org.springframework.security.kerberos.authentication.KerberosServiceRequestToken instance and then is never equals with the one used to create the session.

It's exactly what has been fixed in #35753, but the fix is only for Spring 7.
Could you please backport this change to Spring 6 ?