The APT package manager, used by Debian, Ubuntu, and other Debian-based Linux distributions to install, update, and remove software, has been updated to version 3.3.5.
The main highlight is a substantial performance improvement to APT’s dependency solver. According to the changelog, the latest optimizations make dependency resolution 10–20% faster while reducing page faults by 65%. However, the reported figures apply specifically to the solver, not overall package download or installation speeds.
The update also includes changes to the SAT solver, whose core has been extracted into a separate component. Additionally, APT now handles unprotected package removals consistently, addressing a disagreement between its internal solver behavior and API.
Another notable change concerns repository signing keys. APT 3.3.5 deprecates the use of key fingerprints in the Signed-By configuration option, which controls which signing keys are accepted for a particular software repository.
Instead, the configuration is moving toward specifying keyring files directly. The release also removes support for Signed-By declarations embedded in repository Release files. These changes mainly affect distribution maintainers and administrators managing third-party repositories.
On the development side, the release expands APT’s performance logging capabilities. New counters track stalled CPU cycles, data translation lookaside buffer activity, page faults, and scheduling events.
In addition, a new perf-eval.py tool has been added to analyze performance logs, helping developers identify bottlenecks and evaluate future optimizations.
Finally, APT 3.3.5 includes fixes for AC adapter detection on Debian systems, bounded parsing of build-profile restrictions, adjustments to tests on big-endian architectures, and terminology corrections concerning GPG and OpenPGP.
For more details, see the changelog.
APT 3.3.5 is currently available in Debian Unstable (Sid). Users running Debian Stable or Ubuntu should not expect this version to appear in their regular repositories, as these distros generally maintain their own APT versions rather than adopting new upstream releases.
