Version difference for strtotime('first day of last month')?

Question

In a script that contains

date(\'Y-m-d\', strtotime(\'first day of last month\'))

in version 5.3.10 (localhost) I get, for example, \'2012

Answer 1

date('Y-m-d', strtotime('first day of -1 month'))

Works fine on PHP 7.0