[TYPO3-english] Strange characters at the beginning of page after upgrade

[Claudio Strizzolo]

Hi everybody,
after upgrading the realurl and tt_news extensions to the last version 
(1.9.3 and 3.0.1, respectively) on my Typo3 4.3.5, I've realized that some 
strange characters are prepended at the beginning of the pages:

<?xml version="1.0" encoding="iso-8859-1"?>

The strange characters get displayed before the actual contents of the 
page.
Maybe the problem is not strictly related to the above extensions, however 
I never noticed it.
Any hints?
Thanks in advance

Claudio