diff --git a/_metadata.py b/_metadata.py
index b3cb0440..9669f116 100644
--- a/_metadata.py
+++ b/_metadata.py
@@ -1,2 +1,2 @@
-__extension_version__ = "0.3.0"
+__extension_version__ = "0.4.0"
 __extension_name__ = "pytket-cutensornet"
diff --git a/docs/changelog.rst b/docs/changelog.rst
index 6066ea60..892af085 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -1,6 +1,16 @@
 Changelog
 ~~~~~~~~~
 
+0.4.0 (October 2023)
+--------------------
+
+* API Update. Configuration of ``MPS`` simulation parameters is now done via ``ConfigMPS``.
+* Added a ``value_of_zero`` parameter to ``ConfigMPS`` for the user to indicate the threshold below which numbers are so small that can be interpreted as zero.
+* Added a logger to MPS methods. Use it by setting ``loglevel`` in ``ConfigMPS``.
+* Improved performance of contraction across ``MPS`` methods by hardcoding the contraction paths.
+* Fixed a bug that caused more MPS canonicalisation than strictly required.
+* Fixed a bug where ``simulate`` would not apply the last batch of gates when using ``MPSxMPO``.
+
 0.3.0 (September 2023)
 ----------------------