Ubuntu Phasing

"Phasing" isn't a time-based release — it's a rollout by percentage

Ubuntu doesn't wait to "release" the package at a certain clock time. The package is already fully published in the repository and downloadable right now. What phasing controls is whether apt offers it to your machine yet.

Here's how it works:

1. When a package is published, Ubuntu marks it with an upgrade-probability — a percentage.
2. On day one that's low (e.g. ~10%). Over the next several days it climbs toward 100%.
3. apt computes a stable, sticky hash from your machine's ID. If your machine "lands under" the current percentage, apt sees the new version and upgrades it. If it lands above the percentage, apt deliberately shows the package as held back — no upgrade offered — even though the new version is sitting right there in the repo.
4. Because the hash is deterministic, a given machine stays consistently in-phase or out-of-phase across packages, which lets them reproduce issues and pull the update before it hits everyone.

So when I said "they'll land on schedule," I mean: in a day or two (usually within ~7 days total) the rollout percentage will reach your machine's hash value, and then a normal apt upgrade will just pick them up. Nothing is scheduled at a wall-clock time — it's a gradual, fleet-wide canary roll.

Why it's usually smart to leave them

The point of phasing is that if a package breaks a small subset of test machines, Ubuntu catches it and either fixes it or pauses the rollout before the rest of the fleet installs it. Mesa GPU drivers and nautilus have both caused regressions before, so letting them phase is the safer default.

If you'd rather not wait

You can force them now with:

bash

sudo apt -o APT::Get::Always-Include-Phased-Updates=true upgrade

That overrides the phase gate for this run and installs the latest regardless of the percentage. Totally safe in most cases, it just means you're skipping the canary protection.