New rules registered with the <newRule> keyword don't seem to be activated.
This sample configuration produces the following messages when debug is enabled:
After some investigations it happens that the new Action rule is created but not actually registered in the rule store - the code is commented, see SimpleRuleStore#addRule().
As far as I can tell, the SimpleRuleStore now expects rules to be registered using a Supplier<Action> instead of a rule instance. Unfortunately, the <newRule> action is not updated and keeps registering instances instead of a supplier.
This prevents from registering and using custom rules in a Logback XML configuration.