[Oxibug]

Hi There!

For guys whom using action hook {bbp_forum_metabox}, It was uses ($post_id) and since v2.6.0 they modify the variable into WP_Post object so if you use {$post_id} to get your custom meta values it won’t work and you must modify it to {$post->ID} instead of {$post_id}.

I extremely recommended to make two functions using {version_compare} with bbp_get_version() to solve this.

if( version_compare( bbp_get_version(), '2.6.0', '<' ) ) {
    // Use $post_id
    add_action( 'bbp_forum_metabox', array( $this, 'bbp_forum_metabox' ) );
}
else {
   // Use $post->ID
   add_action( 'bbp_forum_metabox', array( $this, 'bbp_forum_metabox_GTv260' ) );
}