diff --git a/.changelog/unreleased/summary.md b/.changelog/unreleased/summary.md
deleted file mode 100644
index 3484e13d..00000000
--- a/.changelog/unreleased/summary.md
+++ /dev/null
@@ -1,4 +0,0 @@
-Just like the last minor release, this is the massive refactoring release.
-Interfaces have been reworked for friendlier usage.
-Better parsers for improved handling of model checker outputs.
-Golang bindings are introduced.
\ No newline at end of file
diff --git a/.changelog/unreleased/features/Go/2-intro.md b/.changelog/v0.4.0/features/Go/2-intro.md
similarity index 100%
rename from .changelog/unreleased/features/Go/2-intro.md
rename to .changelog/v0.4.0/features/Go/2-intro.md
diff --git a/.changelog/unreleased/features/Go/3-step-runner.md b/.changelog/v0.4.0/features/Go/3-step-runner.md
similarity index 100%
rename from .changelog/unreleased/features/Go/3-step-runner.md
rename to .changelog/v0.4.0/features/Go/3-step-runner.md
diff --git a/.changelog/unreleased/features/Rust/4-event-stream.md b/.changelog/v0.4.0/features/Rust/4-event-stream.md
similarity index 100%
rename from .changelog/unreleased/features/Rust/4-event-stream.md
rename to .changelog/v0.4.0/features/Rust/4-event-stream.md
diff --git a/.changelog/unreleased/features/Rust/5-parallel.md b/.changelog/v0.4.0/features/Rust/5-parallel.md
similarity index 100%
rename from .changelog/unreleased/features/Rust/5-parallel.md
rename to .changelog/v0.4.0/features/Rust/5-parallel.md
diff --git a/.changelog/unreleased/improvements/Rust/6-refactoring.md b/.changelog/v0.4.0/improvements/Rust/6-refactoring.md
similarity index 100%
rename from .changelog/unreleased/improvements/Rust/6-refactoring.md
rename to .changelog/v0.4.0/improvements/Rust/6-refactoring.md
diff --git a/.changelog/unreleased/improvements/Rust/7-parsers.md b/.changelog/v0.4.0/improvements/Rust/7-parsers.md
similarity index 100%
rename from .changelog/unreleased/improvements/Rust/7-parsers.md
rename to .changelog/v0.4.0/improvements/Rust/7-parsers.md
diff --git a/.changelog/unreleased/improvements/Rust/8-temp-dir.md b/.changelog/v0.4.0/improvements/Rust/8-temp-dir.md
similarity index 100%
rename from .changelog/unreleased/improvements/Rust/8-temp-dir.md
rename to .changelog/v0.4.0/improvements/Rust/8-temp-dir.md
diff --git a/.changelog/v0.4.0/summary.md b/.changelog/v0.4.0/summary.md
new file mode 100644
index 00000000..3a5bf031
--- /dev/null
+++ b/.changelog/v0.4.0/summary.md
@@ -0,0 +1,4 @@
+Like the last minor release, this is another massive refactoring release.
+- Reworked interfaces for friendlier usage.
+- Better parsers for improved handling of model checker outputs.
+- Golang bindings.
diff --git a/.changelog/unreleased/test/1-improved-ci.md b/.changelog/v0.4.0/test/1-improved-ci.md
similarity index 100%
rename from .changelog/unreleased/test/1-improved-ci.md
rename to .changelog/v0.4.0/test/1-improved-ci.md
diff --git a/.changelog/unreleased/test/Rust/9-integration-tests.md b/.changelog/v0.4.0/test/Rust/9-integration-tests.md
similarity index 100%
rename from .changelog/unreleased/test/Rust/9-integration-tests.md
rename to .changelog/v0.4.0/test/Rust/9-integration-tests.md
diff --git a/CHANGELOG.md b/CHANGELOG.md
index caee5ef4..ee51d1ca 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,11 +1,11 @@
 # CHANGELOG
 
-## Unreleased
+## v0.4.0
 
-Just like the last minor release, this is the massive refactoring release.
-Interfaces have been reworked for friendlier usage.
-Better parsers for improved handling of model checker outputs.
-Golang bindings are introduced.
+Like the last minor release, this is another massive refactoring release.
+- Reworked interfaces for friendlier usage.
+- Better parsers for improved handling of model checker outputs.
+- Golang bindings.
 
 ### FEATURES
 
diff --git a/rs/Cargo.lock b/rs/Cargo.lock
index 70fc1c4c..0d093723 100644
--- a/rs/Cargo.lock
+++ b/rs/Cargo.lock
@@ -356,7 +356,7 @@ checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
 
 [[package]]
 name = "modelator"
-version = "0.3.1"
+version = "0.4.0"
 dependencies = [
  "clap",
  "clap_generate",
diff --git a/rs/modelator/Cargo.toml b/rs/modelator/Cargo.toml
index 272da6bc..df120f5a 100644
--- a/rs/modelator/Cargo.toml
+++ b/rs/modelator/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "modelator"
 description = "A framework and tools for model-based testing."
-version = "0.3.1"
+version = "0.4.0"
 edition = "2021"
 rust-version = "1.56"
 license = "Apache-2.0"
diff --git a/scripts/prepare_release.sh b/scripts/prepare_release.sh
index c31fa271..aeaf8dcb 100755
--- a/scripts/prepare_release.sh
+++ b/scripts/prepare_release.sh
@@ -10,6 +10,9 @@ git checkout -B "release/v${RELEASE_VERSION}"
 # update the versions on Rust crate
 sed -i "s|^version = \"[^\"]\+\"|version = \"${RELEASE_VERSION}\"|g" "$RUST_DIR/modelator/Cargo.toml"
 
+# update Cargo.lock with latest version
+cargo build --manifest-path "$RUST_DIR/modelator/Cargo.toml"
+
 # update the version on Python module
 # skip python
 # sed -i "s|^version = \"[^\"]\+\"|version = \"${RELEASE_VERSION}\"|g" "$PYTHON_DIR/pyproject.toml"