diff --git a/README.md b/README.md
index 12e5e48..ba2f4e1 100644
--- a/README.md
+++ b/README.md
@@ -326,6 +326,14 @@ It checks each prerequisite, offers pip and winget for what is missing, and
 writes `PassMan-Server-Installer.exe` here. The version comes from
 `server/version.py`.
 
+## Versions
+
+The Windows server has its own version, in `server/version.py`, and each
+release is tagged `v<version>`. It started at 1.0.0 when the repositories
+were split; an installed server from before then says 2.2.0 under Settings →
+Apps, and the 1.0.0 installer upgrades it just the same. The version is
+separate from the app's and from the Linux server's.
+
 ## Project layout
 
 ```
diff --git a/server/version.py b/server/version.py
index 5e23767..6c40683 100644
--- a/server/version.py
+++ b/server/version.py
@@ -1,9 +1,10 @@
 """
-Single source of truth for the server's version.
+Single source of truth for the Windows server's version.
 
 Read by build_version.py for the exe's Properties > Details, and by the
-builder, which passes it to Inno Setup for the installer. Bump it on
-release.
+builder, which passes it to Inno Setup for the installer. Bump it on release
+and tag the release commit v<version>. It started at 1.0.0 and is separate
+from the app's and from the Linux server's.
 """
 
-__version__ = "2.2.0"
+__version__ = "1.0.0"