I was born in 1986-04-21, which is Monday. My next birthday with day name "Monday" is 1997-04-21 and so on.

I wrote the program to find upto 100 year to find which year my birthday comes with matching day name that is monday.

This is the code:

```
<?php
date_default_timezone_set('Asia/Calcutta');
for($year = 1986; $year < 2086; $year++) {
    $timestamp = mktime(0, 0, 0, 4, 21, $year);
    if(date('l', $timestamp) == 'Monday') {
        echo date('Y-m-d, l', $timestamp) . "\n";
    }
}
?>

```

This is the output of the program:

```
1986-04-21, Monday
1997-04-21, Monday
2003-04-21, Monday
2008-04-21, Monday
2014-04-21, Monday
2025-04-21, Monday
2031-04-21, Monday
2036-04-21, Monday

```

Now my problem is why PHP is not supporting before 1970 and after 2040.  

 So how can I get the birthday after 2040 or before 1970?