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<?php $years = 5; $baseDate = new \DateTime(); $baseDate = new \DateTime($baseDate->format('Y-m-01 00:00:00')); $baseDate->modify('-' . $years . ' years'); var_dump($baseDate);
Output for 5.6.0 - 5.6.25, 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.31, 7.4.0 - 7.4.33, 8.0.0 - 8.0.12, 8.0.14 - 8.0.30, 8.1.0 - 8.1.31, 8.2.0 - 8.2.26, 8.3.0 - 8.3.14, 8.4.1
object(DateTime)#2 (3) { ["date"]=> string(26) "2011-09-01 00:00:00.000000" ["timezone_type"]=> int(3) ["timezone"]=> string(16) "Europe/Amsterdam" }
Output for 7.3.32 - 7.3.33, 8.0.13
object(DateTime)#2 (3) { ["date"]=> string(26) "2011-09-01 00:00:00.000000" ["timezone_type"]=> int(3) ["timezone"]=> string(3) "UTC" }

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