Made no difference first time I tried changing that code, but restoring a pre-5.3 backup solved the problem.
Thanks for staying on this. A ‘fix’ would be nice.
So the last line of QuietSkin.php:
public function feedback($string) { /* no output */
}
BECOMES:
public function feedback($string, …$args) { /* no output */
}
And the birds start singing again, right? I’m all over it. Many thanks.