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<?php var_dump(unserialize('a:4:{s:11:"duplication";s:5:"Email";s:17:"extraction_fields";a:5:{i:1;s:9:"FirstName";i:2;s:8:"LastName";i:4;s:5:"Email";i:10;s:11:"__skipField";i:11;s:11:"__skipField";}s:13:"custom_fields";a:0:{}s:12:"magic_fields";a:0:{}}'));
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.12 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
array(4) { ["duplication"]=> string(5) "Email" ["extraction_fields"]=> array(5) { [1]=> string(9) "FirstName" [2]=> string(8) "LastName" [4]=> string(5) "Email" [10]=> string(11) "__skipField" [11]=> string(11) "__skipField" } ["custom_fields"]=> array(0) { } ["magic_fields"]=> array(0) { } }

preferences:
194.92 ms | 406 KiB | 314 Q