i installed 4.5.7 and there are some changings on that alb element.
So if you have a child-theme menu.php uploaded – this will come into conflict with the new settings.
in that case it maybe enough to delete that file. ( Save it first on your desktop)

by the way : if you like to have on logo ( non transparency one) a title tag too – add one line for it above:

function custom_logo_attriubtes(){
?>
<script>
(function($){
  $('.logo img').attr({ title:"custom_title", alt:"custom_alt" });
  $('.logo img.alternate').attr({ title:"transparent Logo", alt:"Alt Transparent" });
})(jQuery);
</script>
<?php
}
add_action('wp_footer', 'custom_logo_attriubtes');

Edit : habe eben mal auf Deutsch Sie gestellt : auch da ist die Suchergebnis Seite auf Deutsch.

well that Logo is the alternate logo – set for transparency Option.
You can add alt and title attribute by child-theme functions.php:

function custom_alternate_logo_attriubtes(){
?>
<script>
(function($){
  $('.logo img.alternate').attr({ title:"Manchester Coach Hire Logo", alt:"Manchester Coach Hire" });
})(jQuery);
</script>
<?php
}
add_action('wp_footer', 'custom_alternate_logo_attriubtes');

maybe we use that class on html (avia_mobile) to only loose that nice animation on ipad and not on small screens:

@media only screen and (min-width:768px) and (max-width: 1024px) {
  .responsive.avia_mobile #top .avia-timeline-vertical .milestone_icon, 
  .responsive.avia_mobile #top .avia-timeline-vertical .av-milestone-indicator, 
  .responsive.avia_mobile #top .avia-timeline-vertical .av-milestone-icon-wrap:after {
    opacity: 1;
    transform: scale(1);
  }
}

by the way : standard default is h2 and h4 – so what version on enfold do you use?

And : thanks to Günter for detailed Info about that new filter ( you only have to ask for it ;) )

By the way the context is the alb element itself : open the alb element and look on top of each alb: there will be somenting like this:

if ( ! class_exists( 'avia_sc_timeline' ) ) 
{
    class avia_sc_timeline extends aviaShortcodeTemplate

so context on this case is : avia_sc_timeline

you can use the new filter: avf_customize_heading_settings
to set the heading tag on that. I do not know it it is possible to change for the years a different heading than for the heading on text.
this comes to child-theme functions.php

function my_avf_customize_heading_settings( array $args, $context, array $extra_args = array() ){
	if( $context == 'avia_sc_timeline' ){
		$args['heading'] = 'h1';						//	change heading from h3 to h1
		$args['extra_class'] = 'my-timeline-class';		//	add an extra class for styling
	}
  return $args;
}
add_filter( 'avf_customize_heading_settings', 'my_avf_customize_heading_settings', 10, 3 );

you can even use p tag or something else

you only have to give that costom class to the timeline alb element ( in this case: my-timeline-class)

PS : alot of the alb elements got this filter now. so only a custom class and the selector is needed to change heading tag.

Also bei mir werden immer noch die Bilder als http angezeigt.

Um sicher zu gehen, dass es nur Umstellungsgründe waren ! Schau mal in die wp-config.php ( Rootverzeichnis deiner Installation)
Manch einer hinterlegt dort die Siteurl – ( selten aber ich hatte mal eine Installation von jemand anderem übernommen – da war es so.) Dann sucht man sich den Wolf , weil diese Einstellung die im Dashboard überschreiben.

ich würde das Plugin Search and Replace nehmen : https://de.wordpress.org/plugins/search-and-replace/

hier :

Das Tool macht im ersten Tab von deiner Datenbank zunächst ein Backup. – sicher ist sicher. – dann Tab3 :
dort würde ich nach
http://pfadi100 suchen lassen und durch https://pfadi100 ersetzen

: Alle Tabellen und Save changes to database
Der zweite Tab wäre bei der Umstellung das Mittel der Wahl gewesen.

But on your media-querrie you got a closing curly bracket – haven’t you?
You see that this here :
@media only screen and (min-width: 780px) {
opens but does not close at the end. and the code for #header .logo img is missing
See : https://kriesi.at/documentation/enfold/menu/#toggle-id-147