Piwigo/include/smarty/docs/designers/language-modifiers/language-modifier-upper.md

upper

This is used to uppercase a variable. This is equivalent to the PHP strtoupper() function.

<?php
$smarty->assign('articleTitle', "If Strike isn't Settled Quickly it may Last a While.");
?>

Where template is:

{$articleTitle}
{$articleTitle|upper}

Will output:

If Strike isn't Settled Quickly it may Last a While.
IF STRIKE ISN'T SETTLED QUICKLY IT MAY LAST A WHILE.

See also lower and capitalize.