Debian 10.5 release mainly adds corrections for security issues, along with a few adjustments for serious problems. Security advisories have already been published separately and are referenced where available.
This is an important release. It incorporates all the recent security fixes from the latest GRUB / Secure Boot “Boothole” security problems. Above all, BootHole should now be addressed with Debian 10.5 as well as not having the boot issues that then plagued some RHEL/CentOS users following mitigations.
Secure Boot shims are signed with a different key to go to upstream this time around: in due course, when revocation of old, insecure code happens to plug the security hole, older media may be deny-listed.
Please note that the point release does not constitute a new version of Debian 10. In other words, it only updates some of the packages included. Therefore, there is no need to throw away old
buster media. After installation, packages can be upgraded to the current versions using an up-to-date Debian mirror.
Upgrading an existing installation to Debian 10.5 release can be achieved by pointing the package management system at one of Debian’s many HTTP mirrors.