Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.  This file is offered as-is,
without any warranty.

Quote from https://www.gnu.org/prep/maintain/html_node/License-Notices-for-Other-Files.html
Older versions of this license did not have the second sentence with the express warranty disclaimer. There is no urgent need to update existing files, but new files should use the new text.