I keep getting this error Call to a member function modify() on boolean with this code

$date_value = the_sub_field( 'date_string' );
$date = DateTime::createFromFormat('d/m/Y', $date_value);
$date->modify('+1 day');  

The last line gives me an error. Both of my formats (display and return inside of ACF) are the same 'd/m/Y'

Really frustrating stuff!

1 Answer 1


the_sub_field() echoes out the sub field. Use get_sub_field() instead.

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