CODE EXAMPLE FOR PHP

Array and string offset access syntax with curly braces is deprecated in tcpdf.php

//Let's say you have something like this in your code:
$str = "test";
echo($str{0});

//since PHP 7.4 curly braces method to get individual characters inside a string has been deprecated, so change the above syntax into this:
$str = "test";
echo($str[0]);