Update PHP version required in frontpage_config.php.
Mark as deprecated in SimpleSAML_Session: DATA_TIMEOUT_LOGOUT, $authority, getAuthority(), getAuthnRequest(), setAuthnRequest(), setIdP(), getIdP(), setSessionIndex(), getSessionIndex(), setNameID(), getNameID(), setSessionDuration(), remainingTime(), isAuthenticated(), getAuthnInstant(), getAttributes(), getAttribute(), setAttributes(), getSize(), expiraDataLogout(), setLogoutState(), getLogoutState().
Rename SimpleSAML_Session::getInstance() to SimpleSAML_Session::getSessionFromRequest(), and leave the former as deprecated.