Hi, is this JCE?
when I search for:
"Array and string offset access syntax with curly braces is no longer supported"
I get:
It's really simple to fix the issue, however keep in mind that you should fork and commit your changes for each library you are using in their repositories to help others as well.
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]);
did you update "jce"
Without looking into it I can only say, that JEM 2.3.5 works fine on a clean Joomla! 3.10.11. with PHP 8.1