[Envira Gallery] Title with Link to Image (LightBox) - Problem

enviratitle.php

<?php

/*
This was working fine, I was able to show Title of image with a hyperlink to image lightbox. 
But suddenly from past a week site was down, when I checked error logs it stated 
that the code (which was in my functions.php) is throwing error - PHP Parse error:  syntax error, unexpected '['

That error was in Line 24 of this code.
*/

function envira_gallery_image_titles( $output, $id, $item, $data, $i ) {
	
    // IDs of galleries to display titles on
    $galleriesToShowTitles = array(
    	245	
    );
    
    // Check if we need to display titles on this gallery
    if ( !in_array( $data['id'], $galleriesToShowTitles ) ) {
    	return $output;
    }
    
    if ( isset( $item['title'] )) {
    	$output .= '<div class="title"><a href="' . $data['gallery'][$id]['link'] . '" class= "envira-gallery-245 envira-gallery-link" title="' . $item['title'] . '" rel="' . ['gallery'] . '" data-thumbnail>' . $item['title'] . '</a></div>';
    }
    
    return $output;
	
}
add_action( 'envira_gallery_output_after_link', 'envira_gallery_image_titles', 10, 5 );