Error when Updating to PHP 7.0 from 5.4 (Kirby 1.1.2)

As I updated my PHP Version of an older Kirby installation 1.1.2 (It wont be updated to Kirby 2 sadly). I have had some error occurring when I make changes in the Backend. Every Change of Content will be applied but I will be given this error after the save:

Notice: Array to string conversion in /var/www/vhosts/websiteurl/httpdocs/kirby/lib/uri.php on line 56

Notice: Indirect modification of overloaded property uriParams::$Array has no effect in /var/www/vhosts/websiteurl/httpdocs/kirby/lib/uri.php on line 56

Does anyone know how this could be fixed?

Try to put curly braces around $parts[0] in this line:

$this->params->$parts[0] = $parts[1];
$this->params->{$parts[0]} = $parts[1];

Thanks that solved it!