Debian 13, Postgres, and the US/* time zones

Original Article ↗ Hacker News Discussion ↗

Debian 13’s removal of legacy `US/*` time zone identifiers from the default `tzdata` package is breaking long-lived configurations in software like PostgreSQL and third‑party tools that still emit these deprecated names. Commenters trace the change back to IANA’s decades‑old move toward continent/city identifiers (e.g., `America/New_York`) to avoid political disputes and ensure historical accuracy, while criticizing how poorly such deprecations are communicated to administrators. The thread widens into broader arguments over best practices for time handling—such as defaulting servers to UTC versus local zones—and the tension between technical consistency and real‑world usage habits.

Background: Debian 13 and tzdata-legacy

  • Debian 13 moved many long-deprecated time zone names (including US/*) into a separate tzdata-legacy package, so they’re no longer installed by default.
  • These aliases have been officially “backward-compatibility” names in the IANA tzdb since the early 1990s, maintained via the backward file.
  • The change affects software still using US/* zones (e.g., Postgres configs, Interactive Brokers TWS, some libraries), which now fail until tzdata-legacy is installed or configs are updated.

Why legacy US/* zones are still used

  • Inertia and muscle memory: old configs get copied forward for decades with little scrutiny.
  • Tutorials, examples, and historical defaults reinforced US/* usage.
  • Some find US/Eastern or “US Pacific” more intuitive and aligned with colloquial/official names than America/New_York.
  • Typing convenience (US/Eastern vs America/New_York) may also play a role.

Time zone naming philosophy and politics

  • tzdb explicitly avoids country-based IDs to sidestep border disputes and maintain historical stability; preferred format is continent/ocean + representative city.
  • Country-based names (e.g., US/*, Poland) are kept only as backward-compatibility aliases.
  • City-based IDs also avoid fights over contested places (e.g., Asia/Jerusalem instead of country-prefixed).
  • Some argue country-based names better reflect that time is defined politically; others counter that countries change more than cities.

Debian behavior and communication

  • Some see Debian’s move as overdue alignment with upstream; others call it a “monstrously stupid” breaking change given how pervasive tzdata is.
  • Frustration that such a widely impactful change wasn’t in Debian 13 release notes; maintainers point to per-package NEWS.Debian and tools like apt-listchanges.
  • Broader complaints: Debian’s habit of downstream patching (e.g., OpenSSH, nginx defaults) and the difficulty of tracking those changes.

Operational lessons: UTC, configs, and future times

  • Many advocate running servers in Etc/UTC and storing timestamps in UTC to avoid a class of bugs, with conversion at the edges.
  • Others note UTC alone is insufficient for future events defined in local civil time (DST and law changes).
  • The thread highlights the need to regularly review configs on upgrades (not just copy old files) and to treat time zones as a moving, political target rather than a stable constant.