Since 1.4.6 we introduced new filters when the registered achievement types and rank types are registered as WordPress post types.

The filter for achievement types is gamipress_public_achievement_{achievement_type_slug} where {achievement_type_slug} should be replaced by the achievement type slug we want to turn private.

An example of this:

// Turn badges achievement type private
add_filter( 'gamipress_public_achievement_badges', '__return_false' );

// Turn quests achievement type private
add_filter( 'gamipress_public_achievement_quests', '__return_false' );

The filter for rank types is gamipress_public_rank_{rank_type_slug} where {rank_type_slug} should be replaced by the rank type slug we want to turn private.

An example of this:

// Turn levels rank type private
add_filter( 'gamipress_public_rank_levels', '__return_false' );

// Turn grades rank type private
add_filter( 'gamipress_public_rank_grades', '__return_false' );