We now have a new User API (see the History section to understand the various ways to get properties for a User and which APIs to use and which ones shouldn't be used).
Example from Java:
@Inject
private UserResolver<UserReference> userResolver;
...
User currentUser = userResolver.resolve(UserReference.CURRENT_USER_REFERENCE);
boolean isActive = currentUser.isActive()
private UserResolver<UserReference> userResolver;
...
User currentUser = userResolver.resolve(UserReference.CURRENT_USER_REFERENCE);
boolean isActive = currentUser.isActive()
Example from Velocity:
$services.user.resolveUser('').isActive()