Need help, block all post but those assigned

The “negation” conditions have been deprecated in favor of “exception” conditions, but unfortunately I have not yet had time to bring the documentation up to date.

Under the Access Conditions tab, select “All Posts” in 1 group, then create another group where you select the posts that should be an exception to the rule. Click on the Settings button and toggle the Exception option to ON.

There is currently no condition to select posts assigned to the current user, but I can see how that could come in handy and have noted it down.