All four of the kept-back packages (base-files, python3-distupgrade, ubuntu-release-upgrader-core, ubuntu-release-upgrader-gtk) were in Phased Updates at the time you asked the question.
- Phased Updates is one precaution to prevent everybody from receiving a buggy package via upgrade: Some people get the upgraded a few days earlier, others a few days later. This provides an opportunity to pause distribution if early folks report problems.
There is nothing wrong. Your system is NOT broken.
Do not try to force the upgrades. Apt will properly install each upgraded package automatically when your turn comes. Phasing typically runs a week or so. Simply run apt update and apt upgrade again in a few days.
- Security upgrades are usually NOT phased. Everybody gets those immediately. The four packages in your question are phased, and therefore NOT security upgrades.
How to see Phased Updates:
$ apt policy base-files base-files: Installed: 12ubuntu4.1 Candidate: 12ubuntu4.2 Version table: 12ubuntu4.2 500 (phased 60%) <------------ There it is! 500 http://us.archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages *** 12ubuntu4.1 100 100 /var/lib/dpkg/status 12ubuntu4 500 500 http://us.archive.ubuntu.com/ubuntu jammy/main amd64 PackagesYou can also see phased update status for some (not all) packages at https://people.canonical.com/%7Eubuntu-archive/phased-updates.html
How to skip phasing, jump to the head of the queue, and install the new package anyway:
Tell apt what you want using the -o (option) flag.
apt -o APT::Get::Always-Include-Phased-Updates=true upgrade- Jumping to the head of the queue is not recommended for most users. You're volunteering to be the tester; for any bugs to affect you first. Bugs in updates are rare, but they do occur.
