diff --git a/Dockerfile b/Dockerfile
index 8fd9be47..00ce1485 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -63,6 +63,9 @@ COPY --chown=app:app migrations/ /app/migrations/
 COPY --chown=app:app scripts/ /app/scripts/
 COPY --chown=app:app docker/ /app/docker/
 COPY --chown=app:app alembic.ini /app/alembic.ini
+# src/_version.py reads the service version from here at runtime, so this
+# is a runtime input as well as a build input.
+COPY --chown=app:app pyproject.toml /app/pyproject.toml
 # Copy config files - this will copy config.toml if it exists, and config.toml.example
 COPY --chown=app:app config.toml* /app/