(NB this is not just missed dist-upgrade. So the question is not a plain duplicate.)
After upgrade to Ubuntu 22.04, I've started getting a strange situation when a package is declared "kept back" without a visible reason. Just now:
# apt-get dist-upgradeReading package lists... DoneBuilding dependency tree... DoneReading state information... DoneCalculating upgrade... DoneThe following packages have been kept back: qemu-block-extra qemu-system-common qemu-system-data qemu-system-gui qemu-system-x86 qemu-utilsThis had been happening with other packages a few days ago on another installation. I've checked hold mark on these packages, no one is present. Discover tool ignores them.
A wild guess about "verbose" mode just resulted in:
# apt-get dist-upgrade -VReading package lists... DoneBuilding dependency tree... DoneReading state information... DoneCalculating upgrade... DoneThe following packages have been kept back: qemu-block-extra (1:6.2+dfsg-2ubuntu6.17 => 1:6.2+dfsg-2ubuntu6.18) qemu-system-common (1:6.2+dfsg-2ubuntu6.17 => 1:6.2+dfsg-2ubuntu6.18) qemu-system-data (1:6.2+dfsg-2ubuntu6.17 => 1:6.2+dfsg-2ubuntu6.18) qemu-system-gui (1:6.2+dfsg-2ubuntu6.17 => 1:6.2+dfsg-2ubuntu6.18) qemu-system-x86 (1:6.2+dfsg-2ubuntu6.17 => 1:6.2+dfsg-2ubuntu6.18) qemu-utils (1:6.2+dfsg-2ubuntu6.17 => 1:6.2+dfsg-2ubuntu6.18)0 upgraded, 0 newly installed, 0 to remove and 6 not upgraded.Package versions seem properly increasing.
A direct request like apt-get install qemu-utils will fix it. But the situation confuses me. This apt-get install doesn't describe why the mass upgrade ignored the packages. Questions:
What factor results in this behavior? Is it a one-shot thing after release upgrade, or this is a regular behavior of the new release?
Is there a option (option set) to ask
apt-getto describe in details why it saves a package from upgrade? (Even in a renowned case like a hold mark.)
UPD: It is suggested "phased updates" may be a reason, see the comments. This looks veracious.