diff --git a/README.md b/README.md
index c804fb5..6a47bcc 100644
--- a/README.md
+++ b/README.md
@@ -111,6 +111,7 @@ Same settings as IIS, just as environment variables in `docker-compose.yml` (nes
 ```yaml
 environment:
   - DataDirectory=/data
+  - TimeZone=UTC
   - Admin__Username=admin
   - Admin__Password=ScratchingPost2026!
   - MaxUploadSizeMB=20
@@ -162,7 +163,11 @@ Any Meow can be given an **Expires** date/time in its editor (under **Scheduling
 - It stays fully intact in **Meows** (with a red **Expired** badge) so it can be re-used or have its expiry pushed back later
 - Nothing is deleted — expiry only affects playback, not the stored slide
 
-Leave it blank for a Meow that should run indefinitely. This is checked using the server's local clock, so make sure the server's time zone is set correctly.
+Leave it blank for a Meow that should run indefinitely.
+
+**Time zone:** expiry is checked against the `TimeZone` setting, not the raw OS clock:
+- **IIS** — `appsettings.json` ships with `"TimeZone": ""`, which falls back to the Windows Server's own local time zone (the original behaviour — no change needed on upgrade).
+- **Docker** — `docker-compose.yml` sets `TimeZone=UTC` by default, since containers are otherwise timezone-ambiguous. Override it to an IANA id (e.g. `Australia/Melbourne`) if you'd rather enter expiry times in local time than UTC; the image includes `tzdata` so real zone names resolve correctly.
 
 ## Display Controls
 
@@ -197,6 +202,7 @@ ScratchingPost/
 │   ├── DisplayController # Device display + playlist API
 │   └── ApiController     # Image upload, ICS parsing
 ├── Data/                # EF Core DbContext + seed data
+├── Infrastructure/      # Clock (time-zone-aware "now" for Meow expiry)
 ├── Models/              # Slide, Device, DeviceSlide
 ├── Routing/             # DeviceSlugConstraint
 ├── Views/               # Razor views (Admin, Slides, Devices, Display)
@@ -214,5 +220,6 @@ ScratchingPost/
 
 ## Version History
 
+- **v1.1.1** — Meow expiry now checked against a configurable `TimeZone` setting instead of the raw OS clock: IIS keeps its existing local-time behaviour by default, Docker defaults to UTC (overridable to any IANA zone; the image ships with `tzdata`)
 - **v1.1.0** — Docker deployment (`Dockerfile` + `docker-compose.yml`, configurable data directory, volume-backed DB/uploads), Meow expiration (`ExpiresAt` field, automatic playback filtering, auto-migrating column for existing databases)
 - **v1.0.0** — Initial release: WYSIWYG slides, embed, ICS calendar, device playlists, drag-and-drop ordering, live polling, IIS-ready deployment