Something funny is going on with CircleCI's build of php 5.3.20. I ran this test using their ssh console to try the other versions of PHP they have installed.

test-run.txt

$ cd /home/ubuntu/.phpenv/versions/
$ for i in *; do echo; echo $i; $i/bin/php ~/test.php ; done

5.3.10
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.3.20
PHP Deprecated:  IntlDateFormatter::setTimeZoneId(): Use datefmt_set_timezone() instead, which also accepts a plain time zone identifier and for which this function is now an alias in /home/ubuntu/test.php on line 3

Deprecated: IntlDateFormatter::setTimeZoneId(): Use datefmt_set_timezone() instead, which also accepts a plain time zone identifier and for which this function is now an alias in /home/ubuntu/test.php on line 3

5.3.25
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.3.3
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.4.10
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.4.11
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.4.12
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.4.13
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.4.14
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.4.15
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.4.4
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.4.5
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.4.6
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.4.7
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.4.8
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

5.4.9
PHP Fatal error:  Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

Fatal error: Class 'IntlDateFormatter' not found in /home/ubuntu/test.php on line 2

test.php

<?php
$a = new IntlDateFormatter('',1,1);
$a->setTimeZoneId(1);