Plugin_Upgrader::active_before

		if ( ! is_wp_version_compatible( $requires_wp ) ) {
			$error = sprintf(
				/* translators: 1: Current WordPress version, 2: Version required by the uploaded plugin. */
				__( 'Your WordPress version is %1$s, however the uploaded plugin requires %2$s.' ),
				$GLOBALS['wp_version'],
				$requires_wp
			);

			return new WP_Error( 'incompatible_wp_required_version', $this->strings['incompatible_archive'], $error );
		}

		return $source;
	}

	/**
	 * Retrieve the path to the file that contains the plugin info.
	 *
	 * This isn't used internally in the class, but is called by the skins.
	 *
	 * @since 2.8.0
	 *
	 * @return string|false The full path to the main plugin file, or false.
	 */