Running K2 under PHP 8.02 throws the following error when trying to save an item:

Fatal error: Array and string offset access syntax with curly braces is no longer supported in /home/b0st0n/public_html/media/k2/assets/vendors/verot/class.upload.php/src/class.upload.php on line 2726

No problem with 7.4, but I wonder if anyone else has had an issue.

Regards,
Alan

Same error :-(

Fatal error: Array and string offset access syntax with curly braces is no longer supported in /home/b0st0n/public_html/media/k2/assets/vendors/verot/class.upload.php/src/class.upload.php on line 2769

Reverted back to 10.3 and fixed the line in question by replacing curly braces with square brackets:

$last = strtolower($size[strlen($size)-1]);

Running PHP 8 in general is probably a bit risky at this point, especially in Joomla sites with a lot of extensions. But it seems to make things a bit more performant.