Serendipity 0.8 and PHP < 4.3
Due to a bug in the version_compare issue in PHP versions prior to 4.3, an Upgrade from Serendipity 0.7.1 to 0.8 may fail.
Because of this error and other security issues in older PHP versions you are urged to upgrade your PHP versions to the latest 4.3 version. Please talk to your hoster to setup a proper version for you, if you do not have access on your own.