ecm:isTrashed was introduced in Nuxeo 10.1 in order to prepare trashed state separation from the lifecycle one.
Nuxeo Server takes care about which property to use when it met ecm:isTrashed in NXQL.
But this is not the case for ecm:currentLifeCycleState='deleted'.
Nuxeo Studio should warn the user when he's using ecm:currentLifeCycleState='deleted'. Message should state that he needs to use the new property ecm:isTrashed.
Message should be shown for Nuxeo version greater or equal to 10.1
When Nuxeo Server version is 10.1+
If my page provider / content view uses ecm:currentLifeCycleState [predicate - could be = "deleted", != 'deleted' too and other variations (IN ('deleted', etc)], a validation warning is shown saying:
Deleted state is deprecated since 10.3 / LTS 2019. We recommend [updating your configuration](https://doc.nuxeo.com/studio/how-to-migrate-trash-configuration in a new page) to prevent warnings at runtime if you upgraded to the new trash service.