An anonymous reader quotes Debian.org:
The Debian project is pleased to announce the first update of its stable distribution Debian 9 (codename "stretch"). This point release mainly adds corrections for security issues, along with a few adjustments for serious problems... Please note that the point release does not constitute a new version of Debian 9 but only updates some of the packages included. There is no need to throw away old "stretch" media... Those who frequently install updates from security.debian.org won't have to update many packages, and most such updates are included in the point release.