Relationship Field Broke

The relationship field, now that you changed it to make the post IDs to save as strings, saves an empty relationship field as an array with a single index that is an empty string. it breaks get_post_meta queries and empty checks against post_meta.

I know why you did the changes to the way it stores relationship values but it ends up creating these: a:1:{i:0;s:0:"";} for empty fields.

I was able to jurry-rig this issue in class acf_field_relationship as follows:

function update_value( $value, $post_id, $field ){
		if(!empty($value)){
			if( is_string($value) ){
				$value = explode(',', $value);
			}elseif( is_object($value) && isset($value->ID) ){
				$value = array( $value->ID );
			}elseif( is_array($value) ){
				foreach( $value as $k => $v ){
					if( is_object($v) && isset($v->ID) ){
						$value[ $k ] = $v->ID;
					}
				}
			}else{
				return $value;
			}
			$value = array_map('strval', $value);
		}
		return $value;
	}

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