Example WP_Query for posts in a CPT published this month.

date-query-example.php

<?php
/**
 * Example WP_Query for posts in a CPT published this month.
 * @link http://codex.wordpress.org/Class_Reference/WP_Query#Date_Parameters
 */
 
// Get today's date. We use this to get the current month/year.
$today = getdate();

// Set up our arguments for the WP_Query.
$args = array(
    'post_type' => 'release', // Set this to your CPT key
    'post_status' => array( 'publish', 'future' ), // Pull out published posts or scheduled ones (no drafts/private)
    'date_query' => array(
        array(
            'year' => $today['year'],
            'month' => $today['mon']
        )
    )
);

// Now create the query.
$releases_query = new WP_Query( $args );