All this subscribe and unsubscribe is ok now, but it's still quite over engineered.

It would be sufficient to keep a private final variable:

private final Consumer<Currency> updateCurrency = currency -> {
			this.currency = currency;
			this.executor.schedule(this.task, 0, TimeUnit.SECONDS);
		};

then subscribe during activate() (or setMeta()) and unsubscribe during deactivate() (or unsetMeta()). No need to keep a List of subscribes when you know you have only one.

You got my comment wrong. With setMeta() I referred to using "Method Injection" (see OSGi compendium 112.3.2 Method Injection https://docs.osgi.org/specification/osgi.cmpn/7.0.0/service.component.html#service.component-method.injection)

In the document it is actually written in British English "Authorisation" and not "Authorisation"

You got my comment wrong. With setMeta() I referred to using "Method Injection" (see OSGi compendium 112.3.2 Method Injection https://docs.osgi.org/specification/osgi.cmpn/7.0.0/service.component.html#service.component-method.injection)