Yesterday, I have changed some symbolic links in /usr/lib32 to point to older version libraries. For example, there was libxml2.so.2 -> libxml2.so.2.6.30 I have changed it to libxml2.so.2.6.27 and my printer stared to work. But after I run 'apt-get upgrade', it returns to its original state. How to prevent this? I think something is choosing the highest version.