<?php
 
$start = 1492894800; //23/04/2017
$end = 1503521999;  //23/08/2017
 
$steps = date('Ym', $end) - date('Ym', $start);
 
$timestamps = array();
for($i = 0; $i <= $steps; $i++) {
	$base = strtotime("+{$i} months", $start);
 
	$timestamps[] = array(
		'from' => $i == 0 ? date('Y-m-d', $start) : date('Y-m-01', $base),
		'to' => $i == $steps ? date('Y-m-d', $end) : date('Y-m-t', $base)
	);
 
//	If we want timestamps	
//	$timestamps[] = array(
//		'from' => strtotime(date('Y-m-01', $base)),
//		'to' => strtotime(date('Y-m-t', $base))
//	);
}
 
print_r($timestamps);

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