libpcre1 is a C library that implements parsing and execution of regular expressions. A lot of packages need some kind of regular expressions, so rather than im

libpcre1 is a C library that implements parsing and execution of regular expressions. A lot of packages need some kind of regular expressions, so rather than implement that themselves they use libpcre. Without libpcre they can't function, so when you uninstall it you must also uninstall everything that requires it. If you were downgrading in order to install some application which isn't compatible with the current versoin of libpcre, then you should be aware that most of the rest of the system may not function with that older version. You should fix your application instead so that it can use the version that comes with SLES12. If you can't you might be able to manually install a second copy of the libpcre1 package, but arrange for it to be in a different location than the normal version. Have fun!