diff --git a/docs/architecture.md b/docs/architecture.md
index bd16b03..8c19942 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -265,3 +265,8 @@ Gitea Actions (`.gitea/workflows/build.yml`), following the tatlock/tatlock-ui p
 
 Firmware is not containerized: it's flashed over USB (`idf.py flash`), with OTA planned
 for phase 5.
+
+**Versioning**: `0.x` while interfaces are still moving — roughly one minor bump per
+roadmap phase (`0.1.x` gateway server-side, `0.2.x` first device firmware, `0.3.x`
+hands-free). **`v1.0.0` is reserved for the wall milestone**: the device mounted in the
+living room, talking to Tatlock end to end.