diff --git a/README.md b/README.md
index fccb55d..431045d 100644
--- a/README.md
+++ b/README.md
@@ -33,6 +33,18 @@ collision-free landing position can be found nearby.
 
 The built mod is written to `build/libs/`.
 
+## Versioning
+
+Rivencraft versions use `x.y.z`:
+
+- `x` changes for a major public release.
+- `y` changes when a development milestone is completed.
+- `z` changes for iterations within the current milestone and for bug fixes.
+
+The patch component resets to zero when a milestone is completed. For example,
+milestone 2 development follows `0.1.1`, `0.1.2`, and so on; completing that
+milestone produces `0.2.0`.
+
 ## Porting approach
 
 Mystcraft Legacy targets Forge for Minecraft 1.12.2. Rivencraft therefore
diff --git a/docs/PORTING.md b/docs/PORTING.md
index 62d044f..edd8705 100644
--- a/docs/PORTING.md
+++ b/docs/PORTING.md
@@ -53,6 +53,18 @@ The temporary shapeless Linking Book recipe makes the linking subsystem easy
 to test. It can move into the writing/bookbinder progression when that system
 is implemented.
 
+## Version policy
+
+Versions follow `x.y.z`:
+
+- `x`: major release point.
+- `y`: number of completed milestones.
+- `z`: iteration within the active milestone, including bug-fix releases.
+
+Starting work on a milestone increments `z`. Completing it increments `y` and
+resets `z` to zero. The first milestone-2 slice is therefore `0.1.1`, and
+milestone 2 completion will be `0.2.0`.
+
 ## Milestone 1 acceptance record
 
 - The project builds on a Java 21 JDK with `./gradlew build`.
diff --git a/gradle.properties b/gradle.properties
index f0ac279..e9d8b44 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -32,7 +32,7 @@ mod_name=Rivencraft
 # The license of the mod. Review your options at https://choosealicense.com/. All Rights Reserved is the default.
 mod_license=LGPL-3.0-or-later
 # The mod version. See https://semver.org/
-mod_version=0.1.0
+mod_version=0.1.1
 # The group ID for the mod. It is only important when publishing as an artifact to a Maven repository.
 # This should match the base package used for the mod sources.
 # See https://maven.apache.org/guides/mini/guide-naming-conventions.html