Page crashed after update, functions not working anymore, footer damaged

Dear,
After I updated wordpress and enfold to the latest versions, our page isn’t working anymore.
The footer on the front page crashed. BUT the footer works on other sub pages.

Furthermore the functions.php in our child theme folder creates errors when using it, even it was working well before the update:

<?php

/*
* Add your own functions here. You can also copy some of the theme functions into this file. 
* WordPress will use those functions instead of the original functions then.
*/

add_action( 'init', 'enfold_customization_switch_fonts' );
function enfold_customization_switch_fonts() {
    global $avia;
    $avia->style->print_extra_output = false;
}

/*prevent roboto fonts loaded by google maps api*/
$child_theme_url = get_stylesheet_directory_uri();
wp_register_script( 'norobotofontbymaps', $child_theme_url.'/norobotofontbymaps.js', 'jquery', "1", true);
wp_enqueue_script( 'norobotofontbymaps' );

// Letzte Bearbeitung von Beiträgen auslesen
function avia_last_mod(){
$output = "
Datum: ". get_the_date(get_option('date_format')) ."
";
return $output; 
}
add_shortcode( 'last_mod', 'avia_last_mod' );

// set Layout of results page in tag cloud
add_filter('avf_blog_style','avia_change_tag_blog_layout', 10, 2); 
function avia_change_tag_blog_layout($layout, $context) {
    if($context == 'tag') $layout = 'blog-grid';
    return $layout;
}

//youtube nocockie
function youtube ($id){
return 
'<div class="avia-video avia-video-16-9" itemprop="video" itemtype="https://schema.org/VideoObject">
<div class="avia-iframe-wrap">
<iframe title="YouTube video player" width="720" height="405" src="https://www.youtube-nocookie.com/embed/'.$id[0].'?enablejsapi=1&ecver=2&showinfo=0&loop=1&rel=0" frameborder="0" allowfullscreen>
</iframe>
</div>
</div>';
}
add_shortcode('youtube', 'youtube');

//Register tag cloud filter callback
add_filter('widget_tag_cloud_args', 'tag_widget_limit');
 
//Limit number of tags inside widget
function tag_widget_limit($args){
 
 //Check if taxonomy option inside widget is set to tags
 if(isset($args['taxonomy']) && $args['taxonomy'] == 'post_tag'){
  $args['number'] = 20; //Limit number of tags
 }
 
 return $args;
}

Could someone please have a look on it?

Thanks, Enrico