Grade against 3.14 too, not just run on it

`requires-python` and the CI pin already said 3.14, but ruff, mypy and pylint
were still grading against 3.10 -- three tools judging an interpreter nothing
runs any more, and ruff withholding the pyupgrade fixes that only become safe
at the newer target. `pin_ci_python.py` rewrites exactly these three knobs.

What the stale target was hiding: 118 sites on `datetime.timezone.utc` instead
of `datetime.UTC` (UP017), two classes still written with `Generic[...]` rather
than PEP 695 syntax, and ruff's stable formatter applying PEP 758 --
`except (A, B):` becomes `except A, B:`. That last one makes the source
3.14-only at the syntax level, which is what `requires-python = ">=3.14"`
already promised; kuhy chose it deliberately over holding ruff a release back
(2026-08-29).

The PEP 695 fix needed a hand: ruff rewrote `class WidgetGroup(Generic[_W])`
to `class WidgetGroup[W: tk.Misc]` but left the body annotated with the
module-level `_W`, a *different* type variable -- mypy caught it as "a function
returning TypeVar should receive at least one argument containing the same
TypeVar". Renamed the body to the new parameter, gave `FrameGroup.__init__`
the concrete `list[tk.Frame]` it always wrapped, and deleted the two now-dead
module-level TypeVars.

ruff, ruff-format, mypy --strict and both pylint passes clean at the new target.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SfnJmxxsZ534AKk16rC2Gr

pyproject.toml

@@ -30,7 +30,7 @@ mcp = ["mcp==2.1.1"]
 include = ["screen_locker*"]
 
 [tool.ruff]
-target-version = "py310"
+target-version = "py314"
 include = ["*.py", "**/*.py"]
 exclude = [".git", ".venv", "__pycache__", "build", "dist", ".eggs"]
 
@@ -140,7 +140,7 @@ line-ending = "auto"
 docstring-code-format = true
 
 [tool.mypy]
-python_version = "3.10"
+python_version = "3.14"
 strict = true
 warn_return_any = true
 warn_unused_configs = true
@@ -174,7 +174,7 @@ init-hook = "import sys; sys.path.insert(0, '.')"
 analyse-fallback-blocks = true
 persistent = true
 jobs = 0
-py-version = "3.10"
+py-version = "3.14"
 ignore = [".venv", "__pycache__"]
 ignore-patterns = [".*\\.pyi$"]
 

screen_locker/_compliance_predicates.py

@@ -14,7 +14,7 @@ rather than at the old ``_compliance_state`` path.
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 import logging
 from typing import TYPE_CHECKING
@@ -40,7 +40,7 @@ _logger = logging.getLogger(__name__)
 
 def _today_str() -> str:
     """Return today's date as ``YYYY-MM-DD`` in UTC."""
-    return datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+    return datetime.now(tz=UTC).strftime("%Y-%m-%d")
 
 
 def is_scheduled_skip_today(

screen_locker/_compliance_state.py

@@ -18,7 +18,7 @@ surfaces the pending opportunity separately via ``AutoUpgradeOpportunity``.
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 from typing import TYPE_CHECKING
 
 from screen_locker._compliance_predicates import (
@@ -79,8 +79,8 @@ def explain_lock_decision(
     order. Heat-skip is never evaluated (it needs a live ``wttr.in`` call) —
     reported via ``heat_skip_evaluated=False``, not guessed.
     """
-    instant = now if now is not None else datetime.now(tz=timezone.utc)
-    today_str = instant.astimezone(timezone.utc).strftime("%Y-%m-%d")
+    instant = now if now is not None else datetime.now(tz=UTC)
+    today_str = instant.astimezone(UTC).strftime("%Y-%m-%d")
     local_dt = instant.astimezone()
     local_minutes = local_dt.hour * 60 + local_dt.minute
 

screen_locker/_decision_log.py

@@ -27,7 +27,7 @@ must never be re-tracked.
 from __future__ import annotations
 
 from dataclasses import dataclass, field
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 import logging
 from pathlib import Path
@@ -94,7 +94,7 @@ class LockDecision:
     def as_record(self) -> dict[str, object]:
         """Render the durable JSON object written to the trail."""
         record: dict[str, object] = {
-            "timestamp": datetime.now(tz=timezone.utc).isoformat(),
+            "timestamp": datetime.now(tz=UTC).isoformat(),
             "locked": self.locked,
             "reason": self.reason,
         }
@@ -179,7 +179,7 @@ def record_no_decision(mode: str, *, log_file: Path | None = None) -> None:
     )
     _append_record(
         {
-            "timestamp": datetime.now(tz=timezone.utc).isoformat(),
+            "timestamp": datetime.now(tz=UTC).isoformat(),
             "locked": None,
             "reason": "mode_makes_no_decision",
             "mode": mode,

screen_locker/_early_bird.py

@@ -9,7 +9,7 @@ its own self-expiring, HMAC-signed state file, mirroring the pattern used by
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 import logging
 
@@ -30,7 +30,7 @@ _logger = logging.getLogger(__name__)
 
 def _today_str() -> str:
     """Return today's date as YYYY-MM-DD in UTC."""
-    return datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+    return datetime.now(tz=UTC).strftime("%Y-%m-%d")
 
 
 class EarlyBirdMixin:
@@ -38,7 +38,7 @@ class EarlyBirdMixin:
 
     def _get_local_time_minutes(self) -> int:
         """Return current local time as minutes from midnight."""
-        now = datetime.now(tz=timezone.utc).astimezone()
+        now = datetime.now(tz=UTC).astimezone()
         return now.hour * 60 + now.minute
 
     def _is_early_bird_time(self) -> bool:

screen_locker/_extra_benefits.py

@@ -13,7 +13,7 @@ State is persisted in ``extra_benefits_state.json`` next to this file.
 
 from __future__ import annotations
 
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 import json
 import logging
 from typing import TYPE_CHECKING, Any
@@ -91,7 +91,7 @@ def process_week_transition(log_file: Path, state_file: Path) -> list[str]:
 
     Returns a list of human-readable reward strings (empty if no transition).
     """
-    now = datetime.now(tz=timezone.utc).astimezone()
+    now = datetime.now(tz=UTC).astimezone()
     current_week_str = _current_iso_week(now)
 
     state = _load_state(state_file)
@@ -108,7 +108,7 @@ def process_week_transition(log_file: Path, state_file: Path) -> list[str]:
         23,
         59,
         59,
-        tzinfo=timezone.utc,
+        tzinfo=UTC,
     )
     prev_week_count = count_weekly_workouts(log_file, today=prev_week_dt)
 
@@ -166,7 +166,7 @@ def weekly_shutdown_bonus_hours(
     state_file: Path, *, today: datetime | None = None
 ) -> int:
     """Return the banked shutdown-time bonus (hours) for the current ISO week."""
-    now = today if today is not None else datetime.now(tz=timezone.utc).astimezone()
+    now = today if today is not None else datetime.now(tz=UTC).astimezone()
     current_week_str = _current_iso_week(now)
     bonus_hours: dict[str, int] = _load_state(state_file).get(
         "weekly_shutdown_bonus_hours", {}
@@ -176,7 +176,7 @@ def weekly_shutdown_bonus_hours(
 
 def has_extended_early_bird(state_file: Path, *, today: datetime | None = None) -> bool:
     """Return True if the current ISO week has an extended early-bird window (09:00)."""
-    now = today if today is not None else datetime.now(tz=timezone.utc).astimezone()
+    now = today if today is not None else datetime.now(tz=UTC).astimezone()
     current_week_str = _current_iso_week(now)
     eb_weeks: list[str] = _load_state(state_file).get(
         "extended_early_bird_iso_weeks", []

screen_locker/_log_mixin.py

@@ -3,7 +3,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass, field
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 import logging
 from typing import TYPE_CHECKING
@@ -107,7 +107,7 @@ def write_signed_entry(
         return RecordResult(appended=False, prior_entries=prior)
 
     entry: dict[str, object] = {
-        "timestamp": datetime.now(tz=timezone.utc).isoformat(),
+        "timestamp": datetime.now(tz=UTC).isoformat(),
         "workout_data": workout_data,
     }
     if workout_id is not None:
@@ -154,5 +154,5 @@ class LogMixin:
         credit only for a genuinely new workout and scale it by whether today
         already had one.
         """
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         return write_signed_entry(self.log_file, today, self.workout_data)

screen_locker/_manual_cli.py

@@ -18,7 +18,7 @@ that can drift.
 from __future__ import annotations
 
 import argparse
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import logging
 from typing import TYPE_CHECKING
 
@@ -132,7 +132,7 @@ def run_manual_log(log_file: Path, argv: Sequence[str]) -> int:
     # UTC, matching how the budget windows compute "today" -- a local date
     # near midnight would file the workout in a different window than the one
     # it is then counted in.
-    date = args.date or datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+    date = args.date or datetime.now(tz=UTC).strftime("%Y-%m-%d")
     draft = _draft(args)
     # Validated here as well as inside the ingest, purely so a person running
     # this by hand gets the concrete field error on stderr and a non-zero exit

screen_locker/_manual_push.py

@@ -22,7 +22,7 @@ what happened, and logs it.
 from __future__ import annotations
 
 from dataclasses import dataclass
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 import logging
 from typing import TYPE_CHECKING
@@ -117,7 +117,7 @@ def _entry_wall_ms(entry: dict, date: str) -> int:
             "for its sync clock",
             date,
         )
-    midnight = datetime.fromisoformat(date).replace(tzinfo=timezone.utc)
+    midnight = datetime.fromisoformat(date).replace(tzinfo=UTC)
     return int(midnight.timestamp() * 1000)
 
 

screen_locker/_manual_workout.py

@@ -15,7 +15,7 @@ see :class:`ManualWorkoutDraft` and :data:`SPORT_CHOICES`.
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import logging
 
 from screen_locker._constants import (
@@ -60,7 +60,7 @@ _logger = logging.getLogger(__name__)
 def _parse_hhmm(value: str) -> datetime | None:
     """Parse an ``HH:MM`` string into a datetime on an arbitrary fixed date."""
     try:
-        return datetime.strptime(value.strip(), "%H:%M").replace(tzinfo=timezone.utc)
+        return datetime.strptime(value.strip(), "%H:%M").replace(tzinfo=UTC)
     except ValueError as exc:
         _logger.warning(
             "Manual workout time %r is not HH:MM (%s) — the workout's duration "

screen_locker/_manual_workout_types.py

@@ -11,7 +11,7 @@ manual workouts are self-reported, so only a few count in any rolling window.
 from __future__ import annotations
 
 from dataclasses import dataclass
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 import logging
 from typing import TYPE_CHECKING
 
@@ -39,13 +39,13 @@ SPORT_LABELS: dict[str, str] = {
 
 def _today_iso() -> str:
     """Return today's date as ``YYYY-MM-DD`` (UTC)."""
-    return datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+    return datetime.now(tz=UTC).strftime("%Y-%m-%d")
 
 
 def _parse_iso(date_str: str) -> datetime | None:
     """Parse ``YYYY-MM-DD`` into a UTC datetime, or return None."""
     try:
-        return datetime.strptime(date_str, "%Y-%m-%d").replace(tzinfo=timezone.utc)
+        return datetime.strptime(date_str, "%Y-%m-%d").replace(tzinfo=UTC)
     except ValueError as exc:
         _logger.warning(
             "Workout log has an unparsable date key %r (%s) — that day is "

screen_locker/_phone_verification.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import date, datetime, timedelta, timezone
+from datetime import UTC, date, datetime, timedelta
 from http import client as _http_client
 import json
 import logging
@@ -119,7 +119,7 @@ class PhoneVerificationMixin(AdbTransportMixin, HttpWorkoutFetchMixin):
         date_str = data.get("date") if data else None
         if not date_str:
             return 0
-        today = datetime.now(tz=timezone.utc).astimezone().date()
+        today = datetime.now(tz=UTC).astimezone().date()
         week_start = today - timedelta(days=today.weekday())
         try:
             entry_date = date.fromisoformat(date_str)

screen_locker/_runnerup_backfill.py

@@ -10,7 +10,7 @@ filled in from whatever RunnerUp kept rather than only from today's check.
 
 from __future__ import annotations
 
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 import logging
 from typing import TYPE_CHECKING
 
@@ -72,7 +72,7 @@ class RunnerUpBackfillMixin:
             )
             return 0
 
-        now = datetime.now(tz=timezone.utc).astimezone()
+        now = datetime.now(tz=UTC).astimezone()
         today = now.date()
         week_start = today - timedelta(days=today.weekday())
 

screen_locker/_runnerup_verification.py

@@ -7,7 +7,7 @@ Root DB fallback lives in ``_runnerup_db.py``.
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import logging
 from typing import Any
 
@@ -77,7 +77,7 @@ class RunnerUpVerificationMixin(
         fails validation), or ``None`` if no today's file exists at all
         (caller should try the root DB path instead).
         """
-        today = datetime.now(tz=timezone.utc).astimezone().strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).astimezone().strftime("%Y-%m-%d")
         exports = self._find_runnerup_exports_for_date(today)
         if not exports:
             _logger.warning(

screen_locker/_shutdown.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import logging
 import subprocess
 from typing import TYPE_CHECKING
@@ -76,7 +76,7 @@ class ShutdownMixin(SickDayStateMixin, WakeAlarmMixin):
 
         Returns True if successful, False otherwise.
         """
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         self._restore_original_config_if_needed()
         if self._sick_mode_used_today():
             _logger.warning("Sick mode already used today")

screen_locker/_shutdown_base.py

@@ -10,7 +10,7 @@ overwrite the fresh base when it runs later in the same startup.
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 import logging
 from typing import TYPE_CHECKING, Any
@@ -62,7 +62,7 @@ def reset_to_base_if_new_day(
 
     Returns True if a reset was performed, False if today was already reset.
     """
-    today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+    today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
 
     if state_file.exists():
         try:

screen_locker/_shutdown_sick_state.py

@@ -10,7 +10,7 @@ earlier, so the following day can put them back.
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 import logging
 
@@ -30,7 +30,7 @@ class SickDayStateMixin:
         try:
             with SICK_DAY_STATE_FILE.open() as f:
                 state = json.load(f)
-            today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+            today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
             return state.get("date") == today
         except (OSError, json.JSONDecodeError) as exc:
             _logger.warning(
@@ -112,7 +112,7 @@ class SickDayStateMixin:
             if loaded is None:
                 return
             state_date, orig_mw, orig_ts = loaded
-            today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+            today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
             if state_date != today:
                 self._write_restored_config(orig_mw, orig_ts, state_date)
         except (OSError, json.JSONDecodeError) as e:

screen_locker/_sick_budget.py

@@ -11,7 +11,7 @@ Loading and saving that history stays in ``_sick_tracker``.
 from __future__ import annotations
 
 from dataclasses import dataclass, field
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 import logging
 from typing import Any
 
@@ -44,13 +44,13 @@ class SickHistory:
 
 def _today_iso() -> str:
     """Return today's date as ``YYYY-MM-DD`` (UTC)."""
-    return datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+    return datetime.now(tz=UTC).strftime("%Y-%m-%d")
 
 
 def _parse_iso(date_str: str) -> datetime | None:
     """Parse ``YYYY-MM-DD`` into a UTC datetime, or return None."""
     try:
-        return datetime.strptime(date_str, "%Y-%m-%d").replace(tzinfo=timezone.utc)
+        return datetime.strptime(date_str, "%Y-%m-%d").replace(tzinfo=UTC)
     except ValueError as exc:
         _logger.warning(
             "Sick history holds an unparsable date %r (%s) — that entry is "

screen_locker/_sick_tracker.py

@@ -7,7 +7,7 @@ state via :func:`save_history`.
 from __future__ import annotations
 
 from dataclasses import dataclass
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 import json
 import logging
 from typing import Any
@@ -60,7 +60,7 @@ def load_history() -> SickHistory:
     try:
         with SICK_HISTORY_FILE.open() as f:
             data = json.load(f)
-    except (OSError, json.JSONDecodeError):
+    except OSError, json.JSONDecodeError:
         _logger.warning("Could not read sick history; starting fresh")
         return SickHistory()
     return SickHistory(
@@ -198,7 +198,7 @@ def add_justification(
     today_str = today or _today_iso()
     entry: dict[str, Any] = {
         "date": today_str,
-        "timestamp": datetime.now(tz=timezone.utc).isoformat(),
+        "timestamp": datetime.now(tz=UTC).isoformat(),
         "symptom": draft.symptom.strip(),
         "onset": draft.onset.strip(),
         "severity": int(draft.severity),

screen_locker/_source_health.py

@@ -19,7 +19,7 @@ accusing the user of skipping a workout they actually did.
 from __future__ import annotations
 
 from dataclasses import dataclass
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 
 from screen_locker._degraded_sources import degraded_sources
 
@@ -49,7 +49,7 @@ def describe_staleness(
             it returned nothing at all.
         now: Injected for tests.
     """
-    instant = now if now is not None else datetime.now(tz=timezone.utc)
+    instant = now if now is not None else datetime.now(tz=UTC)
     if newest is None:
         return SourceFinding(
             name=name,
@@ -60,7 +60,7 @@ def describe_staleness(
                 "your phone writes to."
             ),
         )
-    age = instant - newest.astimezone(timezone.utc)
+    age = instant - newest.astimezone(UTC)
     if age < STALE_AFTER:
         return None
     return SourceFinding(

screen_locker/_status.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import date, datetime, timedelta, timezone
+from datetime import UTC, date, datetime, timedelta
 import json
 import logging
 import sys
@@ -73,7 +73,7 @@ def _print_day_line(d: date, entries: list[dict], sick_days: set[str]) -> bool:
 
 def run_status(locker: ScreenLocker) -> None:
     """Print weekly workout status, run RunnerUp scan, apply bonus, then exit."""
-    today = datetime.now(tz=timezone.utc).astimezone().date()
+    today = datetime.now(tz=UTC).astimezone().date()
     monday = today - timedelta(days=today.weekday())
     log_file: Path = locker.log_file
     log_data = load_workout_log(log_file)
@@ -120,7 +120,7 @@ def run_status(locker: ScreenLocker) -> None:
     eb_str = "Yes — until 09:00" if eb_ext else "No"
 
     # Heat skips this month
-    this_month = datetime.now(tz=timezone.utc).astimezone().date().strftime("%Y-%m")
+    this_month = datetime.now(tz=UTC).astimezone().date().strftime("%Y-%m")
     heat_entries = [
         (d, entry)
         for d, entries in log_data.items()

screen_locker/_status_data.py

@@ -10,7 +10,7 @@ status view are built on.
 
 from __future__ import annotations
 
-from datetime import date, datetime, timedelta, timezone
+from datetime import UTC, date, datetime, timedelta
 from pathlib import Path
 from typing import TYPE_CHECKING
 
@@ -181,7 +181,7 @@ def gather_status(
     Never touches ADB, sudo, or the network — safe to call on every i3blocks
     tick and every status-window open/refresh.
     """
-    instant = now if now is not None else datetime.now(tz=timezone.utc)
+    instant = now if now is not None else datetime.now(tz=UTC)
     today_local = instant.astimezone()
     today_str = today_local.date().isoformat()
 

screen_locker/_surface_group.py

@@ -23,16 +23,13 @@ from __future__ import annotations
 
 import contextlib
 import tkinter as tk
-from typing import TYPE_CHECKING, Generic, TypeVar
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from collections.abc import Callable, Iterator
 
-_W = TypeVar("_W", bound=tk.Misc)
-"""The widget each group mirrors, so a subclass keeps its own methods typed."""
 
-
-class WidgetGroup(Generic[_W]):
+class WidgetGroup[W: tk.Misc]:
     """One logical widget, mirrored onto every monitor.
 
     Only the operations the locker actually performs after creation are
@@ -40,16 +37,16 @@ class WidgetGroup(Generic[_W]):
     from the first copy, since all copies are built identically.
     """
 
-    def __init__(self, widgets: list[_W]) -> None:
+    def __init__(self, widgets: list[W]) -> None:
         """Wrap the per-monitor copies of one widget."""
         self._widgets = widgets
 
-    def __iter__(self) -> Iterator[_W]:
+    def __iter__(self) -> Iterator[W]:
         """Iterate the per-monitor copies, for callers that need each one."""
         return iter(self._widgets)
 
     @property
-    def first(self) -> _W:
+    def first(self) -> W:
         """The primary monitor's copy, for reads that cannot fan out."""
         return self._widgets[0]
 
@@ -111,7 +108,7 @@ class FrameGroup(WidgetGroup[tk.Frame]):
     it to ``_button()`` creates one button inside each of its frames.
     """
 
-    def __init__(self, widgets: list[_W]) -> None:
+    def __init__(self, widgets: list[tk.Frame]) -> None:
         """Wrap the per-monitor frames, tracking which output each came from."""
         super().__init__(widgets)
         self._outputs: list[str] = []

screen_locker/_sync_client.py

@@ -10,7 +10,7 @@ because a silent None here is exactly how the PC stopped syncing for weeks.
 
 from __future__ import annotations
 
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 import logging
 from pathlib import Path
 
@@ -86,7 +86,7 @@ def try_recover_firebase_session() -> RecoveryResult:
             FirebaseCredentials(
                 id_token=body["id_token"],
                 refresh_token=body["refresh_token"],
-                expires_at=datetime.now(tz=timezone.utc)
+                expires_at=datetime.now(tz=UTC)
                 + timedelta(seconds=int(body["expires_in"])),
             )
         )

screen_locker/_sync_retry.py

@@ -27,7 +27,7 @@ from __future__ import annotations
 
 import logging
 from time import sleep
-from typing import TYPE_CHECKING, TypeVar
+from typing import TYPE_CHECKING
 
 from crdt_sync import RemoteSyncError
 
@@ -41,10 +41,8 @@ if TYPE_CHECKING:
 
 _logger = logging.getLogger(__name__)
 
-T = TypeVar("T")
 
-
-def with_sync_retry(
+def with_sync_retry[T](
     operation: Callable[[], T],
     *,
     description: str,

screen_locker/_sync_status.py

@@ -131,7 +131,7 @@ def gather_sync_status(
         # astimezone() with no argument resolves the system local zone, which
         # is what a human reading the status window expects to see.
         last_push = (
-            dt.datetime.fromtimestamp(mtime, tz=dt.timezone.utc)
+            dt.datetime.fromtimestamp(mtime, tz=dt.UTC)
             .astimezone()
             .strftime("%Y-%m-%d %H:%M")
         )

screen_locker/_wake_alarm.py

@@ -8,7 +8,7 @@ change.
 from __future__ import annotations
 
 import calendar
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 import logging
 import subprocess
 
@@ -27,7 +27,7 @@ class WakeAlarmMixin:
     @staticmethod
     def _is_tomorrow_alarm_day() -> bool:
         """Check if tomorrow is an alarm day."""
-        tomorrow = datetime.now(tz=timezone.utc) + timedelta(days=1)
+        tomorrow = datetime.now(tz=UTC) + timedelta(days=1)
         return tomorrow.weekday() in ALARM_DAYS
 
     @staticmethod
@@ -37,7 +37,7 @@ class WakeAlarmMixin:
         Returns:
             Epoch seconds WAKE_AFTER_HOURS from now.
         """
-        wake_time = datetime.now(tz=timezone.utc) + timedelta(
+        wake_time = datetime.now(tz=UTC) + timedelta(
             hours=WAKE_AFTER_HOURS,
         )
         return calendar.timegm(wake_time.utctimetuple())

screen_locker/_wake_state.py

@@ -11,7 +11,7 @@ by patching ``screen_locker._wake_state.WAKE_STATE_FILE``.
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 import logging
 
@@ -24,7 +24,7 @@ _logger = logging.getLogger(__name__)
 
 def _today_str() -> str:
     """Return today's date as YYYY-MM-DD in UTC."""
-    return datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+    return datetime.now(tz=UTC).strftime("%Y-%m-%d")
 
 
 def load_wake_state() -> dict[str, object] | None:
@@ -39,7 +39,7 @@ def load_wake_state() -> dict[str, object] | None:
     try:
         with WAKE_STATE_FILE.open() as f:
             state = json.load(f)
-    except (OSError, json.JSONDecodeError):
+    except OSError, json.JSONDecodeError:
         _logger.warning("Cannot read wake state file")
         return None
 

screen_locker/_weekly_check.py

@@ -11,7 +11,7 @@ current ISO week (Mon-Sun).
 
 from __future__ import annotations
 
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 import logging
 from typing import TYPE_CHECKING
 
@@ -67,7 +67,7 @@ def is_relaxed_day(*, today: datetime | None = None) -> bool:
     Returns:
         True when the current weekday is Tuesday, Wednesday, or Thursday.
     """
-    dt = today if today is not None else datetime.now(tz=timezone.utc).astimezone()
+    dt = today if today is not None else datetime.now(tz=UTC).astimezone()
     return dt.weekday() in _RELAXED_WEEKDAYS
 
 
@@ -92,7 +92,7 @@ def count_weekly_workouts(
     Returns:
         The weekly workout count (Mon-Sun, up to and including today).
     """
-    dt = today if today is not None else datetime.now(tz=timezone.utc).astimezone()
+    dt = today if today is not None else datetime.now(tz=UTC).astimezone()
     week_start = (dt - timedelta(days=dt.weekday())).date()
     today_date = dt.date()
 
@@ -100,9 +100,7 @@ def count_weekly_workouts(
     for date_str, entries in load_workout_log(log_file).items():
         try:
             entry_date = (
-                datetime.strptime(date_str, "%Y-%m-%d")
-                .replace(tzinfo=timezone.utc)
-                .date()
+                datetime.strptime(date_str, "%Y-%m-%d").replace(tzinfo=UTC).date()
             )
         except ValueError as exc:
             _logger.warning(

screen_locker/tests/_unlock_helpers.py

@@ -7,7 +7,7 @@ leading underscore so pre-commit's name-tests-test hook skips it.
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import MagicMock
@@ -36,7 +36,7 @@ def setup_unlock(
     if seed_today_type is None:
         log_file.write_text("{}")
     else:
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         log_file.write_text(
             json.dumps(
                 {

screen_locker/tests/conftest.py

@@ -11,7 +11,7 @@ Safety:
 from __future__ import annotations
 
 from contextlib import ExitStack
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from pathlib import Path
 from typing import TYPE_CHECKING
@@ -183,7 +183,7 @@ def _isolate_shutdown_base(tmp_path: Path) -> Iterator[None]:
     same as the rest of the suite already does.
     """
     target = tmp_path / "shutdown_base.json"
-    today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+    today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
     target.write_text(
         json.dumps(
             {"base_mon_wed_hour": 21, "base_thu_sun_hour": 21, "last_reset_date": today}

screen_locker/tests/test_compliance_state.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import patch
@@ -20,7 +20,7 @@ if TYPE_CHECKING:
 
 
 def _today() -> str:
-    return datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+    return datetime.now(tz=UTC).strftime("%Y-%m-%d")
 
 
 class TestIsScheduledSkipToday:

screen_locker/tests/test_compliance_state_part2.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import patch
@@ -15,7 +15,7 @@ if TYPE_CHECKING:
 
 
 def _today() -> str:
-    return datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+    return datetime.now(tz=UTC).strftime("%Y-%m-%d")
 
 
 class TestExplainLockDecision:
@@ -47,7 +47,7 @@ class TestExplainLockDecision:
         files["early_bird_pending_file"].write_text(
             json.dumps({"date": _today(), "hmac": "sig"})
         )
-        now = datetime.now(tz=timezone.utc).astimezone().replace(hour=6, minute=0)
+        now = datetime.now(tz=UTC).astimezone().replace(hour=6, minute=0)
         with patch(
             "screen_locker._compliance_predicates.verify_entry_hmac", return_value=True
         ):
@@ -69,7 +69,7 @@ class TestExplainLockDecision:
         files["early_bird_pending_file"].write_text(
             json.dumps({"date": _today(), "hmac": "sig"})
         )
-        now = datetime.now(tz=timezone.utc).astimezone().replace(hour=10, minute=0)
+        now = datetime.now(tz=UTC).astimezone().replace(hour=10, minute=0)
         with patch(
             "screen_locker._compliance_predicates.verify_entry_hmac", return_value=True
         ):
@@ -97,7 +97,7 @@ class TestExplainLockDecision:
             extended_early_bird=False,
             weekly_minimum_met=False,
             relaxed_day=False,
-            now=datetime.now(tz=timezone.utc).astimezone().replace(hour=12, minute=0),
+            now=datetime.now(tz=UTC).astimezone().replace(hour=12, minute=0),
         )
         assert result.fired is False
         assert result.stage == "sick_day"
@@ -114,9 +114,7 @@ class TestExplainLockDecision:
                 extended_early_bird=False,
                 weekly_minimum_met=False,
                 relaxed_day=False,
-                now=datetime.now(tz=timezone.utc)
-                .astimezone()
-                .replace(hour=12, minute=0),
+                now=datetime.now(tz=UTC).astimezone().replace(hour=12, minute=0),
             )
         assert result.fired is False
         assert result.stage == "already_logged"
@@ -130,14 +128,14 @@ class TestExplainLockDecision:
             weekly_minimum_met=False,
             relaxed_day=False,
             wake_skip=True,
-            now=datetime.now(tz=timezone.utc).astimezone().replace(hour=12, minute=0),
+            now=datetime.now(tz=UTC).astimezone().replace(hour=12, minute=0),
         )
         assert result.fired is False
         assert result.stage == "wake_alarm_skip"
 
     def test_fresh_early_bird_time_skips(self, tmp_path: Path) -> None:
         files = self._files(tmp_path)
-        now = datetime.now(tz=timezone.utc).astimezone().replace(hour=6, minute=0)
+        now = datetime.now(tz=UTC).astimezone().replace(hour=6, minute=0)
         result = explain_lock_decision(
             **files,
             sick_history=SickHistory(),
@@ -156,7 +154,7 @@ class TestExplainLockDecision:
     ) -> None:
         """The re-check time isn't ambiguous — it's whichever one actually applies."""
         files = self._files(tmp_path)
-        now = datetime.now(tz=timezone.utc).astimezone().replace(hour=6, minute=0)
+        now = datetime.now(tz=UTC).astimezone().replace(hour=6, minute=0)
         result = explain_lock_decision(
             **files,
             sick_history=SickHistory(),
@@ -178,7 +176,7 @@ class TestExplainLockDecision:
             extended_early_bird=False,
             weekly_minimum_met=False,
             relaxed_day=True,
-            now=datetime.now(tz=timezone.utc).astimezone().replace(hour=12, minute=0),
+            now=datetime.now(tz=UTC).astimezone().replace(hour=12, minute=0),
         )
         assert result.fired is False
         assert result.stage == "relaxed_day"
@@ -202,7 +200,7 @@ class TestExplainLockDecision:
             extended_early_bird=False,
             weekly_minimum_met=False,
             relaxed_day=True,
-            now=datetime.now(tz=timezone.utc).astimezone().replace(hour=12, minute=0),
+            now=datetime.now(tz=UTC).astimezone().replace(hour=12, minute=0),
         )
         assert result.fired is False
         assert result.stage == "relaxed_day_already_skipped"
@@ -215,7 +213,7 @@ class TestExplainLockDecision:
             extended_early_bird=False,
             weekly_minimum_met=True,
             relaxed_day=False,
-            now=datetime.now(tz=timezone.utc).astimezone().replace(hour=12, minute=0),
+            now=datetime.now(tz=UTC).astimezone().replace(hour=12, minute=0),
         )
         assert result.fired is False
         assert result.stage == "weekly_minimum_met"
@@ -228,7 +226,7 @@ class TestExplainLockDecision:
             extended_early_bird=False,
             weekly_minimum_met=False,
             relaxed_day=False,
-            now=datetime.now(tz=timezone.utc).astimezone().replace(hour=12, minute=0),
+            now=datetime.now(tz=UTC).astimezone().replace(hour=12, minute=0),
         )
         assert result.fired is True
         assert result.stage == "full_lock_pending_heat_check"

screen_locker/tests/test_early_bird_part2.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from pathlib import Path
 from typing import Any
@@ -49,7 +49,7 @@ class TestTryAutoUpgradeEarlyBird:
         assert result is True
         with log_file.open() as f:
             data: dict[str, Any] = json.load(f)
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         assert data[today][0]["workout_data"]["type"] == "phone_verified"
         assert data[today][0]["workout_data"]["after_early_bird"] == "true"
 

screen_locker/tests/test_early_bird_part3.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING, Any
 from unittest.mock import MagicMock, patch
@@ -81,7 +81,7 @@ class TestIsEarlyBirdPending:
     ) -> None:
         """Return False when HMAC verification fails."""
         locker = create_locker(mock_tk, tmp_path)
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         pending_file = tmp_path / "early_bird_pending.json"
         pending_file.write_text(json.dumps({"date": today, "hmac": "bad"}))
         with (
@@ -105,7 +105,7 @@ class TestIsEarlyBirdPending:
     ) -> None:
         """Return True when today's marker is present and HMAC-valid."""
         locker = create_locker(mock_tk, tmp_path)
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         pending_file = tmp_path / "early_bird_pending.json"
         pending_file.write_text(json.dumps({"date": today, "hmac": "sig"}))
         with (
@@ -125,7 +125,7 @@ class TestIsEarlyBirdPending:
     ) -> None:
         """Unsigned marker is accepted when no HMAC key is configured."""
         locker = create_locker(mock_tk, tmp_path)
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         pending_file = tmp_path / "early_bird_pending.json"
         pending_file.write_text(json.dumps({"date": today}))
         with (
@@ -163,7 +163,7 @@ class TestSaveEarlyBirdPending:
         assert pending_file.exists()
         with pending_file.open() as f:
             data: dict[str, Any] = json.load(f)
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         assert data["date"] == today
         assert not locker.log_file.exists()
 

screen_locker/tests/test_extra_benefits.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import MagicMock, patch
@@ -73,7 +73,7 @@ class TestProcessWeekTransition:
         self, tmp_path: Path
     ) -> None:
         """Early return when ISO week already processed (line 63)."""
-        now = datetime.now(tz=timezone.utc).astimezone()
+        now = datetime.now(tz=UTC).astimezone()
         year, week, _ = now.isocalendar()
         f = tmp_path / "state.json"
         f.write_text(json.dumps({"last_processed_iso_week": f"{year}-W{week:02d}"}))
@@ -81,7 +81,7 @@ class TestProcessWeekTransition:
 
     @staticmethod
     def _current_week_str() -> str:
-        now = datetime.now(tz=timezone.utc).astimezone()
+        now = datetime.now(tz=UTC).astimezone()
         year, week, _ = now.isocalendar()
         return f"{year}-W{week:02d}"
 
@@ -148,7 +148,7 @@ class TestProcessWeekTransition:
         ):
             process_week_transition(tmp_path / "log.json", f)
 
-        now = datetime.now(tz=timezone.utc).astimezone()
+        now = datetime.now(tz=UTC).astimezone()
         year, week, _ = now.isocalendar()
         state = json.loads(f.read_text())
         assert f"{year}-W{week:02d}" in state["extended_early_bird_iso_weeks"]
@@ -202,7 +202,7 @@ class TestProcessWeekTransition:
 
     def test_duplicate_eb_week_not_added_twice(self, tmp_path: Path) -> None:
         """Current week already in EB list: not added again (line 91 branch False)."""
-        now = datetime.now(tz=timezone.utc).astimezone()
+        now = datetime.now(tz=UTC).astimezone()
         year, week, _ = now.isocalendar()
         current_week = f"{year}-W{week:02d}"
         f = tmp_path / "state.json"

screen_locker/tests/test_extra_benefits_part2.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING
 
@@ -26,7 +26,7 @@ class TestWeeklyShutdownBonusHours:
 
     def test_returns_current_week_bonus(self, tmp_path: Path) -> None:
         """Returns the banked bonus for the current ISO week."""
-        now = datetime.now(tz=timezone.utc).astimezone()
+        now = datetime.now(tz=UTC).astimezone()
         year, week, _ = now.isocalendar()
         current_week = f"{year}-W{week:02d}"
         f = tmp_path / "state.json"
@@ -71,7 +71,7 @@ class TestHasExtendedEarlyBird:
 
     def test_returns_true_when_current_week_is_in_list(self, tmp_path: Path) -> None:
         """Current ISO week present in list → True."""
-        now = datetime.now(tz=timezone.utc).astimezone()
+        now = datetime.now(tz=UTC).astimezone()
         year, week, _ = now.isocalendar()
         current_week = f"{year}-W{week:02d}"
         f = tmp_path / "state.json"
@@ -82,6 +82,6 @@ class TestHasExtendedEarlyBird:
         """An explicit `today` is used instead of the real wall clock."""
         f = tmp_path / "state.json"
         f.write_text(json.dumps({"extended_early_bird_iso_weeks": ["2024-W01"]}))
-        fixed_today = datetime(2024, 1, 5, tzinfo=timezone.utc)
+        fixed_today = datetime(2024, 1, 5, tzinfo=UTC)
         assert has_extended_early_bird(f, today=fixed_today) is True
         assert has_extended_early_bird(f) is False

screen_locker/tests/test_home_isolation.py

@@ -16,7 +16,7 @@ which is the only warning that arrives before the credential is already gone.
 
 from __future__ import annotations
 
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 import os
 from pathlib import Path
 
@@ -32,7 +32,7 @@ def _fixture_credentials() -> FirebaseCredentials:
     return FirebaseCredentials(
         id_token=f"{fixture}-id-token",
         refresh_token=f"{fixture}-refresh-token",
-        expires_at=datetime.now(tz=timezone.utc) + timedelta(hours=1),
+        expires_at=datetime.now(tz=UTC) + timedelta(hours=1),
     )
 
 

screen_locker/tests/test_init_and_log.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 import tkinter as tk
 from typing import TYPE_CHECKING
@@ -142,7 +142,7 @@ class TestHasLoggedToday:
     ) -> None:
         """Test when today's workout is logged with valid HMAC."""
         log_file = tmp_path / "log.json"
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         log_file.write_text(
             json.dumps({today: {"workout": "data", "hmac": "valid"}}),
         )
@@ -163,7 +163,7 @@ class TestHasLoggedToday:
     ) -> None:
         """Test rejects entry when HMAC verification fails."""
         log_file = tmp_path / "log.json"
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         log_file.write_text(
             json.dumps({today: {"workout": "data", "hmac": "tampered"}}),
         )
@@ -184,7 +184,7 @@ class TestHasLoggedToday:
     ) -> None:
         """Accept unsigned entry when HMAC key is unavailable."""
         log_file = tmp_path / "log.json"
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         log_file.write_text(
             json.dumps({today: {"workout": "data"}}),
         )
@@ -211,7 +211,7 @@ class TestHasLoggedToday:
     ) -> None:
         """Reject unsigned entry when HMAC key IS available."""
         log_file = tmp_path / "log.json"
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         log_file.write_text(
             json.dumps({today: {"workout": "data"}}),
         )

screen_locker/tests/test_init_and_log_part2.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 import tkinter as tk
 from typing import TYPE_CHECKING, Any
@@ -66,7 +66,7 @@ class TestAutoUpgradeSickDay:
             assert locker._try_auto_upgrade_sick_day() is True
             mock_adjust.assert_called_once()
 
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         with log_file.open() as f:
             data: dict[str, Any] = json.load(f)
         # The log is day-keyed with a LIST of workouts; the upgrade appends one.

screen_locker/tests/test_init_and_log_part3.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING, Any
 from unittest.mock import MagicMock, patch
@@ -36,7 +36,7 @@ class TestSaveWorkoutLog:
         assert log_file.exists()
         with log_file.open() as f:
             data: dict[str, Any] = json.load(f)
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         assert today in data
         # The log now holds a list of entries per day (multiple workouts/day).
         assert data[today][0]["workout_data"]["type"] == "running"
@@ -61,7 +61,7 @@ class TestSaveWorkoutLog:
 
         with log_file.open() as f:
             data: dict[str, Any] = json.load(f)
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         assert "hmac" not in data[today][0]
 
     def test_save_to_existing_file(
@@ -86,7 +86,7 @@ class TestSaveWorkoutLog:
         with log_file.open() as f:
             data: dict[str, Any] = json.load(f)
         assert "2020-01-01" in data
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         assert today in data
 
     def test_save_with_corrupted_existing_file(
@@ -110,7 +110,7 @@ class TestSaveWorkoutLog:
 
         with log_file.open() as f:
             data: dict[str, Any] = json.load(f)
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         assert today in data
 
     def test_save_with_write_error(

screen_locker/tests/test_manual_push.py

@@ -3,7 +3,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import patch
@@ -61,9 +61,7 @@ class TestEntryWallMs:
 
     def test_uses_the_entry_timestamp(self) -> None:
         """Uses the entry timestamp."""
-        expected = int(
-            datetime(2026, 7, 13, 12, tzinfo=timezone.utc).timestamp() * 1000
-        )
+        expected = int(datetime(2026, 7, 13, 12, tzinfo=UTC).timestamp() * 1000)
         ms = _entry_wall_ms({"timestamp": "2026-07-13T12:00:00+00:00"}, "2026-07-13")
         assert ms == expected
 
@@ -74,7 +72,7 @@ class TestEntryWallMs:
 
     def test_missing_timestamp_falls_back_to_midnight(self) -> None:
         """Missing timestamp falls back to midnight."""
-        expected = int(datetime(2026, 7, 13, tzinfo=timezone.utc).timestamp() * 1000)
+        expected = int(datetime(2026, 7, 13, tzinfo=UTC).timestamp() * 1000)
         assert _entry_wall_ms({}, "2026-07-13") == expected
 
     def test_fallback_is_stable_across_calls(self) -> None:

screen_locker/tests/test_manual_sync.py

@@ -3,6 +3,7 @@
 
 from __future__ import annotations
 
+from datetime import UTC
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import patch
@@ -189,6 +190,6 @@ class TestIngestManualRecords:
 
 
 def _dt(date: str) -> object:
-    from datetime import datetime, timezone
+    from datetime import datetime
 
-    return datetime.strptime(date, "%Y-%m-%d").replace(tzinfo=timezone.utc)
+    return datetime.strptime(date, "%Y-%m-%d").replace(tzinfo=UTC)

screen_locker/tests/test_manual_workout.py

@@ -4,7 +4,7 @@
 from __future__ import annotations
 
 import dataclasses
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 import json
 from typing import TYPE_CHECKING
 
@@ -145,7 +145,7 @@ class TestIsBudgetExhausted:
         # MANUAL_WORKOUT_BUDGET_PER_30_DAYS distinct dates, all strictly after
         # the 30d cutoff (2026-06-05) but at/before the 7d cutoff (2026-06-28),
         # so only the 30d window sees them.
-        today_dt = datetime.strptime(_TODAY, "%Y-%m-%d").replace(tzinfo=timezone.utc)
+        today_dt = datetime.strptime(_TODAY, "%Y-%m-%d").replace(tzinfo=UTC)
         dates = [
             (today_dt - timedelta(days=8 + i)).strftime("%Y-%m-%d")
             for i in range(MANUAL_WORKOUT_BUDGET_PER_30_DAYS)

screen_locker/tests/test_phone_verification_part5.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import date, datetime, timedelta, timezone
+from datetime import UTC, date, datetime, timedelta
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import MagicMock, patch
@@ -17,7 +17,7 @@ if TYPE_CHECKING:
 # ISO week. On a Monday no such day exists (week_start == today), so using
 # date.today() made them fail every Monday and pass Tue-Sun. Pin "now" to a
 # Wednesday instead: yesterday is then Tuesday, comfortably inside the week.
-_FROZEN_NOW = datetime(2026, 7, 22, 12, 0, tzinfo=timezone.utc)  # a Wednesday
+_FROZEN_NOW = datetime(2026, 7, 22, 12, 0, tzinfo=UTC)  # a Wednesday
 _FROZEN_YESTERDAY = (_FROZEN_NOW.date() - timedelta(days=1)).isoformat()
 
 

screen_locker/tests/test_scheduled_skip.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import MagicMock, patch
@@ -46,7 +46,7 @@ class TestIsScheduledSkipToday:
     ) -> None:
         """Returns True when today's date is in the skips list."""
         locker = self._make_locker(mock_tk, tmp_path)
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         skip_file = tmp_path / "scheduled_skips.json"
         skip_file.write_text(json.dumps([today]))
         with patch(
@@ -128,7 +128,7 @@ class TestScheduledSkipEarlyExit:
 
     @staticmethod
     def _write_today_skip(tmp_path: Path) -> None:
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         skip_file = tmp_path / "scheduled_skips.json"
         skip_file.write_text(json.dumps([today]))
 

screen_locker/tests/test_screen_lock_coverage_part3.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import MagicMock, patch
@@ -64,7 +64,7 @@ class TestTryAutoUpgradeSickDayRunnerUp:
             result = locker._try_auto_upgrade_sick_day()
 
         assert result is True
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         data = json.loads(log_file.read_text())
         assert data[today][0]["workout_data"]["type"] == "runnerup_verified"
         assert data[today][0]["workout_data"]["after_sick_day"] == "true"
@@ -141,7 +141,7 @@ class TestTryAutoUpgradeEarlyBirdRunnerUp:
             result = locker._try_auto_upgrade_early_bird()
 
         assert result is True
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         data = json.loads(log_file.read_text())
         assert data[today][0]["workout_data"]["type"] == "runnerup_verified"
         assert data[today][0]["workout_data"]["after_early_bird"] == "true"

screen_locker/tests/test_session_sync.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 from typing import TYPE_CHECKING
 from unittest.mock import patch
 
@@ -19,7 +19,7 @@ if TYPE_CHECKING:
 
 _DATE = "2026-08-21"
 # The ISO week _DATE falls in, for count_weekly_workouts.
-_TODAY = datetime(2026, 8, 21, tzinfo=timezone.utc)
+_TODAY = datetime(2026, 8, 21, tzinfo=UTC)
 
 
 def _session(**overrides: object) -> dict:

screen_locker/tests/test_shutdown_base.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import MagicMock
@@ -58,7 +58,7 @@ class TestResetToBaseIfNewDay:
 
     def test_returns_false_when_already_reset_today(self, tmp_path: Path) -> None:
         """Same-day last_reset_date → early False return (line 63)."""
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         f = tmp_path / "state.json"
         f.write_text(json.dumps({"last_reset_date": today}))
         assert reset_to_base_if_new_day(f, self._make_mixin()) is False

screen_locker/tests/test_shutdown_part3.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+from datetime import UTC
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import MagicMock, patch
@@ -68,9 +69,9 @@ class TestRestoreOriginalConfigIfNeeded:
     ) -> None:
         """Test does not restore when state date matches today."""
         locker = create_locker(mock_tk, tmp_path)
-        from datetime import datetime, timezone
+        from datetime import datetime
 
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         state_file = tmp_path / "state.json"
         state_file.write_text(
             json.dumps(

screen_locker/tests/test_shutdown_part5.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+from datetime import UTC
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import MagicMock, patch
@@ -44,9 +45,9 @@ class TestSickModeUsedToday:
             "screen_locker._shutdown_sick_state.SICK_DAY_STATE_FILE",
             state_file,
         ):
-            from datetime import datetime, timezone
+            from datetime import datetime
 
-            today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+            today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
             state_file.write_text(json.dumps({"date": today}))
             assert locker._sick_mode_used_today() is True
 

screen_locker/tests/test_source_health.py

@@ -7,7 +7,7 @@ correctly while the phone had stopped writing to it nine days earlier.
 
 from __future__ import annotations
 
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 
 from screen_locker import _sync_client
 from screen_locker._source_health import (
@@ -17,7 +17,7 @@ from screen_locker._source_health import (
     explain_findings,
 )
 
-_NOW = datetime(2026, 8, 24, 12, 0, tzinfo=timezone.utc)
+_NOW = datetime(2026, 8, 24, 12, 0, tzinfo=UTC)
 
 
 class TestCollectSourceFindings:
@@ -50,7 +50,7 @@ class TestDescribeStaleness:
 
     def test_nine_day_silence_is_reported_with_its_age(self) -> None:
         """The real 2026-08-15 mirror silence, named in days."""
-        newest = datetime(2026, 8, 15, 18, 0, tzinfo=timezone.utc)
+        newest = datetime(2026, 8, 15, 18, 0, tzinfo=UTC)
 
         finding = describe_staleness("GitHub mirror", newest, now=_NOW)
 

screen_locker/tests/test_status.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+from datetime import UTC
 import json
 from pathlib import Path
 from typing import TYPE_CHECKING
@@ -82,9 +83,9 @@ class TestRunStatusNormal:
         self, tmp_path: Path, capsys: pytest.CaptureFixture
     ) -> None:
         """Today == the week's Sunday: the per-day loop runs all 7 days, never breaking early."""
-        from datetime import datetime, timezone
+        from datetime import datetime
 
-        fixed_now = datetime(2026, 7, 5, 12, 0, tzinfo=timezone.utc)  # a real Sunday
+        fixed_now = datetime(2026, 7, 5, 12, 0, tzinfo=UTC)  # a real Sunday
         eb_file = tmp_path / "eb.json"
         log_file = tmp_path / "log.json"
         locker = _make_locker(log_file, n_filled=0)
@@ -106,9 +107,9 @@ class TestRunStatusNormal:
         self, tmp_path: Path, capsys: pytest.CaptureFixture
     ) -> None:
         """A date with no workout_log entry but in sick_history → shown as sick_day."""
-        from datetime import datetime, timezone
+        from datetime import datetime
 
-        today = datetime.now(tz=timezone.utc).astimezone().date().isoformat()
+        today = datetime.now(tz=UTC).astimezone().date().isoformat()
         eb_file = tmp_path / "eb.json"
         log_file = tmp_path / "log.json"
         history_file = tmp_path / "sick_history.json"
@@ -188,9 +189,9 @@ class TestRunStatusWorkoutLog:
         self, tmp_path: Path, capsys: pytest.CaptureFixture
     ) -> None:
         """Log entry with counted type → ✓ mark printed."""
-        from datetime import datetime, timezone
+        from datetime import datetime
 
-        today = datetime.now(tz=timezone.utc).astimezone().date().isoformat()
+        today = datetime.now(tz=UTC).astimezone().date().isoformat()
         log_file = tmp_path / "log.json"
         log_file.write_text(
             json.dumps(
@@ -223,9 +224,9 @@ class TestRunStatusWorkoutLog:
         self, tmp_path: Path, capsys: pytest.CaptureFixture
     ) -> None:
         """Log entry with uncounted type → ✗ mark printed."""
-        from datetime import datetime, timezone
+        from datetime import datetime
 
-        today = datetime.now(tz=timezone.utc).astimezone().date().isoformat()
+        today = datetime.now(tz=UTC).astimezone().date().isoformat()
         log_file = tmp_path / "log.json"
         log_file.write_text(
             json.dumps({today: {"workout_data": {"type": "heat_skip", "source": ""}}})

screen_locker/tests/test_status_data.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
@@ -11,9 +11,9 @@ if TYPE_CHECKING:
 # Fixed reference instant: Friday 2024-01-05, 12:00 UTC == 13:00 Europe/Warsaw.
 # Outside the 05:00-09:00 early-bird window and not a Tue/Wed/Thu relaxed day,
 # so lock-decision branches are fully deterministic regardless of wall clock.
-_FRIDAY_NOON_UTC = datetime(2024, 1, 5, 12, 0, tzinfo=timezone.utc)
+_FRIDAY_NOON_UTC = datetime(2024, 1, 5, 12, 0, tzinfo=UTC)
 # Monday of that same ISO week, for Mon-Wed shutdown-band assertions.
-_MONDAY_NOON_UTC = datetime(2024, 1, 1, 12, 0, tzinfo=timezone.utc)
+_MONDAY_NOON_UTC = datetime(2024, 1, 1, 12, 0, tzinfo=UTC)
 
 
 def _files(tmp_path: Path) -> dict[str, Path]:

screen_locker/tests/test_status_data_part2.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import date, datetime, timezone
+from datetime import UTC, date, datetime
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import patch
@@ -16,9 +16,9 @@ if TYPE_CHECKING:
 # Fixed reference instant: Friday 2024-01-05, 12:00 UTC == 13:00 Europe/Warsaw.
 # Outside the 05:00-09:00 early-bird window and not a Tue/Wed/Thu relaxed day,
 # so lock-decision branches are fully deterministic regardless of wall clock.
-_FRIDAY_NOON_UTC = datetime(2024, 1, 5, 12, 0, tzinfo=timezone.utc)
+_FRIDAY_NOON_UTC = datetime(2024, 1, 5, 12, 0, tzinfo=UTC)
 # Monday of that same ISO week, for Mon-Wed shutdown-band assertions.
-_MONDAY_NOON_UTC = datetime(2024, 1, 1, 12, 0, tzinfo=timezone.utc)
+_MONDAY_NOON_UTC = datetime(2024, 1, 1, 12, 0, tzinfo=UTC)
 
 
 class TestGatherStatus:

screen_locker/tests/test_status_data_part3.py

@@ -7,7 +7,7 @@ weekly minimum) means no lock is needed.
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import patch
@@ -21,9 +21,9 @@ if TYPE_CHECKING:
 # Fixed reference instant: Friday 2024-01-05, 12:00 UTC == 13:00 Europe/Warsaw.
 # Outside the 05:00-09:00 early-bird window and not a Tue/Wed/Thu relaxed day,
 # so lock-decision branches are fully deterministic regardless of wall clock.
-_FRIDAY_NOON_UTC = datetime(2024, 1, 5, 12, 0, tzinfo=timezone.utc)
+_FRIDAY_NOON_UTC = datetime(2024, 1, 5, 12, 0, tzinfo=UTC)
 # Monday of that same ISO week, for Mon-Wed shutdown-band assertions.
-_MONDAY_NOON_UTC = datetime(2024, 1, 1, 12, 0, tzinfo=timezone.utc)
+_MONDAY_NOON_UTC = datetime(2024, 1, 1, 12, 0, tzinfo=UTC)
 
 
 class TestGatherStatusLockSuppression:
@@ -84,7 +84,7 @@ class TestGatherStatusLockSuppression:
     def test_relaxed_day_stops_lock(self, tmp_path: Path) -> None:
         """Tuesday is a relaxed day — is_relaxed_day derives it from `now`."""
         files = _files(tmp_path)
-        tuesday_noon = datetime(2024, 1, 2, 12, 0, tzinfo=timezone.utc)
+        tuesday_noon = datetime(2024, 1, 2, 12, 0, tzinfo=UTC)
         with patch(
             "screen_locker._status_data.has_workout_skip_today", return_value=False
         ):

screen_locker/tests/test_status_data_part4.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import patch
@@ -16,9 +16,9 @@ if TYPE_CHECKING:
 # Fixed reference instant: Friday 2024-01-05, 12:00 UTC == 13:00 Europe/Warsaw.
 # Outside the 05:00-09:00 early-bird window and not a Tue/Wed/Thu relaxed day,
 # so lock-decision branches are fully deterministic regardless of wall clock.
-_FRIDAY_NOON_UTC = datetime(2024, 1, 5, 12, 0, tzinfo=timezone.utc)
+_FRIDAY_NOON_UTC = datetime(2024, 1, 5, 12, 0, tzinfo=UTC)
 # Monday of that same ISO week, for Mon-Wed shutdown-band assertions.
-_MONDAY_NOON_UTC = datetime(2024, 1, 1, 12, 0, tzinfo=timezone.utc)
+_MONDAY_NOON_UTC = datetime(2024, 1, 1, 12, 0, tzinfo=UTC)
 
 
 class TestFormatSummaryLine:

screen_locker/tests/test_status_part2.py

@@ -5,6 +5,7 @@ Split from test_status.py to stay under the repo's 400-line file limit.
 
 from __future__ import annotations
 
+from datetime import UTC
 from typing import TYPE_CHECKING
 from unittest.mock import MagicMock, patch
 
@@ -142,9 +143,9 @@ class TestRunStatusMinimumStatus:
         self, tmp_path: Path, capsys: pytest.CaptureFixture
     ) -> None:
         """Pin today to Monday so the loop hits d > today on day 2, covering line 64."""
-        from datetime import datetime, timezone
+        from datetime import datetime
 
-        fake_now = datetime(2026, 6, 22, 12, 0, tzinfo=timezone.utc)
+        fake_now = datetime(2026, 6, 22, 12, 0, tzinfo=UTC)
 
         class _FakeDatetime(datetime):
             @classmethod

screen_locker/tests/test_status_part3.py

@@ -5,6 +5,7 @@ Split out of test_status.py for the 250-line cap.
 
 from __future__ import annotations
 
+from datetime import UTC
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import patch
@@ -32,9 +33,9 @@ class TestWeeklyTotalUsesPerWorkoutRule:
         days are supposed to support. Also covers manual workouts counting
         individually (no once-per-day collapse), same as verified ones.
         """
-        from datetime import datetime, timezone
+        from datetime import datetime
 
-        today = datetime.now(tz=timezone.utc).astimezone().date().isoformat()
+        today = datetime.now(tz=UTC).astimezone().date().isoformat()
         log_file = tmp_path / "log.json"
         log_file.write_text(
             json.dumps(

screen_locker/tests/test_verify_workout.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING
 from unittest.mock import MagicMock
@@ -54,7 +54,7 @@ class TestIsSickDayToday:
     ) -> None:
         """Return True when today is in sick_history's sick_days list."""
         locker = create_locker(mock_tk, tmp_path)
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         history_file = tmp_path / "sick_history.json"
         history_file.write_text(json.dumps({"sick_days": [today]}))
         assert locker._is_sick_day_today() is True

screen_locker/tests/test_wake_shutdown.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+from datetime import UTC
 from typing import TYPE_CHECKING
 from unittest.mock import MagicMock, patch
 
@@ -22,13 +23,13 @@ class TestIsTomorrowAlarmDay:
     ) -> None:
         """Sunday evening → Monday is alarm day (weekday=0)."""
         locker = create_locker(mock_tk, tmp_path)
-        from datetime import datetime, timezone
+        from datetime import datetime
 
         # Sunday 2026-04-12 → tomorrow Monday
         with patch(
             "screen_locker._wake_alarm.datetime",
         ) as mock_dt:
-            mock_dt.now.return_value = datetime(2026, 4, 12, 23, 0, tzinfo=timezone.utc)
+            mock_dt.now.return_value = datetime(2026, 4, 12, 23, 0, tzinfo=UTC)
             mock_dt.side_effect = datetime
             from datetime import timedelta
 
@@ -47,7 +48,7 @@ class TestIsTomorrowAlarmDay:
     ) -> None:
         """Monday evening → Tuesday is NOT an alarm day."""
         locker = create_locker(mock_tk, tmp_path)
-        from datetime import datetime, timedelta, timezone
+        from datetime import datetime, timedelta
 
         # Monday 2026-04-13 → tomorrow Tuesday (weekday=1)
         with (
@@ -59,7 +60,7 @@ class TestIsTomorrowAlarmDay:
                 timedelta,
             ),
         ):
-            mock_dt.now.return_value = datetime(2026, 4, 13, 23, 0, tzinfo=timezone.utc)
+            mock_dt.now.return_value = datetime(2026, 4, 13, 23, 0, tzinfo=UTC)
             mock_dt.side_effect = datetime
             assert locker._is_tomorrow_alarm_day() is False
 
@@ -71,7 +72,7 @@ class TestIsTomorrowAlarmDay:
     ) -> None:
         """Thursday evening → Friday is alarm day (weekday=4)."""
         locker = create_locker(mock_tk, tmp_path)
-        from datetime import datetime, timedelta, timezone
+        from datetime import datetime, timedelta
 
         # Thursday 2026-04-16 → tomorrow Friday (weekday=4)
         with (
@@ -83,7 +84,7 @@ class TestIsTomorrowAlarmDay:
                 timedelta,
             ),
         ):
-            mock_dt.now.return_value = datetime(2026, 4, 16, 23, 0, tzinfo=timezone.utc)
+            mock_dt.now.return_value = datetime(2026, 4, 16, 23, 0, tzinfo=UTC)
             mock_dt.side_effect = datetime
             assert locker._is_tomorrow_alarm_day() is True
 

screen_locker/tests/test_weekly_check.py

@@ -3,7 +3,7 @@ has_weekly_minimum."""
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from typing import TYPE_CHECKING, Any
 from unittest.mock import patch
@@ -25,7 +25,7 @@ if TYPE_CHECKING:
 def _dt(weekday: int, hour: int = 10) -> datetime:
     """Return a UTC-aware datetime for the given ISO weekday (0=Mon, 6=Sun)."""
     # 2025-05-19 is a Monday (weekday 0)
-    base = datetime(2025, 5, 19, hour, 0, 0, tzinfo=timezone.utc)
+    base = datetime(2025, 5, 19, hour, 0, 0, tzinfo=UTC)
     from datetime import timedelta
 
     return base + timedelta(days=weekday)

screen_locker/tests/test_weekly_logic_part5.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 from pathlib import Path
 from typing import TYPE_CHECKING
 from unittest.mock import patch
@@ -34,7 +34,7 @@ class TestRelaxedDayAlreadySkippedBranch:
         # script_dir.parent/"log.json" resolves to tmp_path/"log.json" -- NOT
         # tmp_path/"screen_locker"/"log.json".
         log_file = tmp_path / "log.json"
-        today = datetime.now(tz=timezone.utc).strftime("%Y-%m-%d")
+        today = datetime.now(tz=UTC).strftime("%Y-%m-%d")
         write_signed_entry(log_file, today, {"type": "relaxed_day_skip"})
 
         with (

scripts/add_scheduled_skip.py

@@ -20,7 +20,7 @@ Usage:
 from __future__ import annotations
 
 import argparse
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 from pathlib import Path
 import sys
@@ -97,7 +97,7 @@ def main(argv: list[str] | None = None) -> int:
 
     date = _today() if args.date == "today" else args.date
     try:
-        datetime.strptime(date, "%Y-%m-%d").replace(tzinfo=timezone.utc)
+        datetime.strptime(date, "%Y-%m-%d").replace(tzinfo=UTC)
     except ValueError:
         msg = f"ERROR: {date!r} is not a YYYY-MM-DD date"
         raise SystemExit(msg) from None

scripts/check_enforcement_armed.py

@@ -94,7 +94,7 @@ def _run(args: list[str]) -> tuple[int, str]:
             timeout=_TIMEOUT_SECONDS,
             check=False,
         )
-    except (OSError, subprocess.SubprocessError):
+    except OSError, subprocess.SubprocessError:
         # A check that cannot run must not look like a check that passed.
         _logger.exception("Could not run %s", " ".join(args))
         return 1, ""

scripts/fix_2026_07_26_sport.py

@@ -29,7 +29,7 @@ Usage (needs the root-owned key at /etc/workout-locker/hmac.key):
 from __future__ import annotations
 
 import argparse
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 import logging
 from pathlib import Path
@@ -152,7 +152,7 @@ def main() -> int:
         _logger.info("\nDry run. Re-run with --apply to write.")
         return 0
 
-    stamp = datetime.now(tz=timezone.utc).strftime("%Y%m%dT%H%M%SZ")
+    stamp = datetime.now(tz=UTC).strftime("%Y%m%dT%H%M%SZ")
     backup = LOG_FILE.with_suffix(f".json.bak-{stamp}")
     shutil.copy2(LOG_FILE, backup)
     _logger.info("\nBacked up to %s", backup)

scripts/revoke_sick_day.py

@@ -22,7 +22,7 @@ Usage:
 from __future__ import annotations
 
 import argparse
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 import json
 import logging
 from pathlib import Path
@@ -73,7 +73,7 @@ def revoke(history: dict, log: dict, date: str) -> str:
         revocations.append(
             {
                 "date": date,
-                "revoked_at": datetime.now(tz=timezone.utc).isoformat(),
+                "revoked_at": datetime.now(tz=UTC).isoformat(),
                 "reason": (
                     "workout was completed but the locker could not read it; "
                     "no local log entry survives for this date"
@@ -92,7 +92,7 @@ def revoke(history: dict, log: dict, date: str) -> str:
     revocations.append(
         {
             "date": date,
-            "revoked_at": datetime.now(tz=timezone.utc).isoformat(),
+            "revoked_at": datetime.now(tz=UTC).isoformat(),
             "reason": (
                 "workout verified after the fact; the sick day was spent only "
                 "because the locker could not read the synced workout"