Using dependencies from older WildFly release, clients are unable to connect to latest WildFly using DIGEST-MD5 mechanism:

java.lang.RuntimeException: javax.security.sasl.SaslException: Authentication failed: all available authentication mechanisms failed:
   DIGEST-MD5: Server rejected authentication

JBOSS-LOCAL-USER method works. I'm talking about latest WildFly with legacy security realms.

We are supposed to maintain backward compatibility with older clients but in this case older client won't work against newer server.