Ubuntu 26.10 is replacing its D-Bus implementation for the first time since 2004, swapping dbus-daemon for dbus-broker – a change end-users are unlikely to notice.
Processes on your desktop talk to each other and to the host system using D-Bus, a ‘message’ bus. This is what the Ubuntu Dock uses to show unread-count badges for apps, what tells your desktop a USB drive has been plugged in, and so on.
Two buses are in play. There’s aa system bus, shared across the whole device, handling hardware and background services, and a user session bus to handle desktop and app integrations for the person logged in.
Users won’t see much of a change; Canonical says everything “keeps working as before”
Ubuntu has used dbus-daemon as its default message bus since its first release 22 years ago. Starting with Ubuntu 26.10, it switches over to dbus-broker for both buses – but what’s the difference?
The dbus-daemon package is the reference implementation of D-Bus, which Ubuntu has used since 2004. Though it’s stable and well documented, it is known to silently drop messages under heavy load, and finds message targets by scanning them one at a time (i.e., slow).
The dbus-broker package is a somewhat-newer version, rewritten from scratch with an ‘asynchronous, event-driven’ design. It should mean no message goes missing and lookups happen quicker, even as the bus fills up with more processes.
Many other desktop Linux distributions already use the newer broker. Ubuntu’s journey has simply taken a little longer for a couple of packaging reasons (not the only low-level swap happening this cycle as Ubuntu is also switching its time sync daemon to a Rust rewrite).
First, Ubuntu policy doesn’t allow two packages that do the same job to sit in main1. And, every package already in main had to drop its dependency on dbus-daemon before dbus-broker could be added. GDM, the GNOME log-in manager, was the last major holdout.
Second, AppArmor, Ubuntu’s security confinement framework, handles D-Bus messages for a subset of system Debian packages as well as all snaps. As dbus-broker only reached feature parity with dbus-daemon relatively recently, swapping it out sooner wasn’t sensible.
But with both hurdles cleared, and a short-term interim release proving ideal opportunity for system changes, Ubuntu 26.10 is all-aboard the dbus-broker2.
Not that you’ll notice.
Dbus-broker is a drop-in replacement
Much like the ‘benefits’ of Dracut in Ubuntu, you shouldn’t notice a change at all. Canonical says dbus-broker uses the “same protocol, same config files, same bus policies” as dbus-daemon, meaning apps, desktop environments and everything else “keeps working as before”.
As dbus-broker is graduating to main in Ubuntu 26.10, the old dbus and dbus-daemon packages are to be dropped down to the universe pocket, and no longer preinstalled. If needed as a dependency for other software (not in main),the old version can still be pulled in.
Implementation wise, dbus-broker package has systemd units for its system and user instances, dbus-broker.service, aliased to the dbus.service units from dbus-daemon. If both packages are installed on the same system, the new one takes priority.
How to use dbus-broker on Ubuntu 26.04
Ubuntu’s been planning a dbus upgrade for a while. While it’s set to be the new, out-of-the-box default starting with Ubuntu 26.10, you can install it on 26.04 LTS (albeit with the obvious caveat that on you’re making a manual change, pulling in a package from universe).
To try it out, just install the dbus-broker from the repos (it’s not in main in resolute, fyi):
sudo apt install dbus-broker
Reboot your system and on the bring up it will be in place. You can check by running systemctl status dbus-broker in your terminal.
You may encounter issues on 26.04 since it wasn’t intended to be default there.
To revert to the vanilla dbus implantation, first make sure the dbus package is still installed. Then, disable dbus-broker via systemd.
sudo systemctl disable dbus-broker
sudo systemctl --user --global disable dbus-broker
As before, reboot your system and log back in to notice …how much you don’t notice a change? Let me know in the comments.
- This is the primary supported Ubuntu repo where the bulk of core/integral packages that make up the distro live. Packages don’t get to hang out in main for the lols. ↩︎
- I’ve had “We Like To Party (The Vengabus)” by Vengaboys in my head whilst writing this. “The dbus-broker’s coming, and everybody’s jumping, New York to San Francisco, an interprocess disco…” ↩︎