Features
- New parameters: author__in, author__not_in, category__and, category__in, category__not_in, post__in, post__not_in, post_name__in, post_parent, post_parent__in, post_parent__not_in, tag__and, tag__in, tag__not_in, tag_slug__and, tag_slug__in. More information. Wherever WordPress requires an array, you submit the elements as comma-separated list:
...&tag__in=12,15.