Fixing the update was the diagnosis; this is the treatment. A clean apt update only refreshed the catalogue - the actual upgrades still wait, and they deserve the same care: look first, read the summary, then install.
The errors are gone and apt update ends the way it should - quietly. Many people stop here, which means their machine has a perfect catalogue of updates it has never installed. This final page of the series completes the job: how to review the pending list, run the upgrade while reading what apt tells you, handle kept-back packages and restarts, and set up the small weekly habit that stops the errors-and-upgrades mountain from ever forming again.
Now that sudo apt update runs cleanly, be clear about what it did: it refreshed the catalogue - the lists of what versions exist. It did not change a single program on your PC. sudo apt upgrade is the step that downloads and installs those newer versions. Running upgrade on stale lists is how people "update" for months while installing nothing new, so the pair always travels together, update first, upgrade second, in the same sitting.
apt list --upgradable. A short list is a routine day; a list of hundreds means the machine has been unpatched for a long time.sudo apt upgrade and read the summary before pressing Y. It states how many packages upgrade, whether anything is newly installed, and - most importantly - whether anything will be removed. Removals on a plain upgrade should be rare; if a program you depend on is listed for removal, stop and investigate instead of accepting.sudo apt full-upgrade is for. Read its summary even more carefully, because full-upgrade is allowed to remove packages to satisfy dependencies.The healthiest Ubuntu is updated in small, frequent steps, and Ubuntu can do most of it alone: automatic security updates (unattended-upgrades) are on by default on a standard install - the same service that occasionally holds the apt lock you may have met while fixing the update. Leave it on. Your manual job shrinks to a weekly sudo apt update and sudo apt upgrade, a two-minute habit that keeps lists short, surprises rare, and the difference between "working system" and "system I am afraid to touch" permanently small.
The video runs the first clean update after the fix, reviews the upgradable list, and completes the upgrade safely.
▶️ Watch Full Videoapt upgrade installs newer versions but will not remove packages or install new dependencies that change the set - anything needing that is reported as kept back. apt full-upgrade (the old dist-upgrade) is allowed to install new dependencies and remove conflicting packages to complete the upgrade, which is sometimes necessary, for example for kernel and driver transitions. Use upgrade routinely, and full-upgrade when kept-back packages persist - reading its removal list carefully before accepting.
No. Most application updates take effect the next time the program starts. A restart is needed when the kernel was upgraded - you keep running the old kernel until you reboot - and for a few core components like systemd. Ubuntu tells you plainly when a restart is required, either in the terminal output or through a notification, so follow that signal rather than restarting on a schedule.
Almost never. First run sudo dpkg --configure -a to finish configuring anything left half-done, then sudo apt --fix-broken install if apt suggests dependency damage, then sudo apt update and sudo apt upgrade again. This sequence resolves the large majority of interrupted upgrades. What you should not do is reboot repeatedly or start deleting package files by hand - the repair commands exist precisely for this state.