CaRP: Caching RSS Parser - Documentation
CaRP Interactive FAQ
Unless you're currently using a very old version, you can simply overwrite carp.php, carpinc.php with the files from the new version. If you are installing CaRP Evolution, also upload the plugins directory and its contents. With any CaRP version, upload the themes directory and its contents (but don't overwrite any themes files that you have modified).
NOTE: If you have modified carpconf.php, do not
overwrite it unless you have copied your changes into the new file first.