diff --git a/CHANGELOG.md b/CHANGELOG.md
index 97556689..03507330 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,31 @@
 # Changelog
 
+## [4.0.0] - 2024-02-29
+
+### Added
+
+- Python 3.11 support.
+- Purification of Gaussian states.
+- `PureFockState.get_tensor_representation` for embeddng the state vector into
+  a tensor with rank equal to the number of modes.
+- Batch processing of pure Fock states.
+- CVQNN module.
+- Support for `tf.function` in `PureFockSimulator`.
+- Supporting JAX in `PureFockSimulator`.
+
+### Fixed
+
+- Error in custom gradient of passive linear gates in `PureFockSimulator`.
+
+### Breaking changes
+
+- Python 3.7 support dropped.
+- `TensorflowPureFockSimulator` has been deleted. Instead, one can use
+  `PureFockSimulator` with `TensorflowCalculator` specified.
+- Printing format of Fock states have been changed.
+- Renamed `_state_vector` to `state_vector`.
+
+
 ## [3.0.0] - 2023-10-23
 
 ### Added
diff --git a/piquasso/__init__.py b/piquasso/__init__.py
index 635da75d..cf4f8483 100644
--- a/piquasso/__init__.py
+++ b/piquasso/__init__.py
@@ -177,4 +177,4 @@
     "cvqnn",
 ]
 
-__version__ = "3.0.0"
+__version__ = "4.0.0"
diff --git a/setup.py b/setup.py
index 7dde68c8..deeae6fa 100644
--- a/setup.py
+++ b/setup.py
@@ -22,7 +22,7 @@
 
 setup(
     name="piquasso",
-    version="3.0.0",
+    version="4.0.0",
     packages=find_packages(exclude=["tests.*", "tests", "scripts", "scripts.*"]),
     maintainer="Budapest Quantum Computing Group",
     maintainer_email="kolarovszki@inf.elte.hu",