diff --git a/CHANGES b/CHANGES
index 327ba977..d6ab9d92 100644
--- a/CHANGES
+++ b/CHANGES
@@ -13,6 +13,17 @@ The rules for this file:
   * release numbers follow "Semantic Versioning" https://semver.org
 
 ------------------------------------------------------------------------------
+??/??/2024 orbeckst
+
+  * 2.3.1
+
+Changes:
+  - alchemlyb adopts SPEC 0 (replaces NEP 29)
+    https://scientific-python.org/specs/spec-0000/
+
+Fixes
+  - Support matplotlib 3.9.0 (issue alchemistry/flamel#28, PR#319).
+
 
 21/05/2024 xiki-tempula
 
diff --git a/devtools/conda-envs/test_env.yaml b/devtools/conda-envs/test_env.yaml
index a8795f1c..bef524b7 100644
--- a/devtools/conda-envs/test_env.yaml
+++ b/devtools/conda-envs/test_env.yaml
@@ -8,7 +8,7 @@ dependencies:
 - pymbar>=4
 - scipy
 - scikit-learn
-- matplotlib
+- matplotlib>=3.7
 - loguru
 - pyarrow
 
diff --git a/docs/index.rst b/docs/index.rst
index edd9b8cf..4350bbaf 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -52,14 +52,12 @@ Development is done in the open on `GitHub`_.
 Software engineering best-practices are used throughout, including continuous integration testing via Github Actions, up-to-date documentation, and regular releases.
 
 .. Note::
-   With release 0.5.0, the alchemlyb project adopted `NEP 29`_ to determine which versions of Python and NumPy_ will be supported.
-   When we release a new major or minor version, alchemlyb will support *at least all minor versions of Python introduced and released in the prior 42 months from the release date with a minimum of 2 minor versions of Python*, and *all minor versions of NumPy released in the prior 24 months from the anticipated release date with a minimum of 3 minor versions of NumPy*.
-
-The pandas_ package (one of our other primary dependencies) also follows `NEP 29`_ so this support policy will make it easier to maintain **alchemlyb** in the future.
+   The alchemlyb project uses `SPEC 0`_ to determine which versions of  Python, NumPy_, and pandas_  will be supported.
+   When we release a new major or minor version, alchemlyb will support *at least all minor versions of Python introduced and released in the prior 3 years from the release date*, and *all minor versions of NumPy and pandas released in the prior 2 years from the anticipated release date*.
 
    
 .. _`GitHub`: https://github.com/alchemistry/alchemlyb
-.. _`NEP 29`: https://numpy.org/neps/nep-0029-deprecation_policy.html
+.. _`SPEC 0`: https://scientific-python.org/specs/spec-0000/
 .. _NumPy: https://numpy.org
 .. _pandas: https://pandas.pydata.org/
 
diff --git a/environment.yml b/environment.yml
index 025ff953..95512668 100644
--- a/environment.yml
+++ b/environment.yml
@@ -9,5 +9,5 @@ dependencies:
 - scipy
 - scikit-learn
 - pyarrow
-- matplotlib
+- matplotlib>=3.7
 - loguru
diff --git a/setup.py b/setup.py
index 49802343..bd39fffd 100755
--- a/setup.py
+++ b/setup.py
@@ -51,7 +51,7 @@
         "pymbar>=4",
         "scipy",
         "scikit-learn",
-        "matplotlib",
+        "matplotlib>=3.7",
         "loguru",
         "pyarrow",
     ],
diff --git a/src/alchemlyb/visualisation/ti_dhdl.py b/src/alchemlyb/visualisation/ti_dhdl.py
index cfdb2238..1cd91728 100644
--- a/src/alchemlyb/visualisation/ti_dhdl.py
+++ b/src/alchemlyb/visualisation/ti_dhdl.py
@@ -222,6 +222,6 @@ def getInd(r=ri, z=[0]):
         color="#151B54",
     )
     lege = ax.legend(prop=FP(size=14), frameon=False, loc=1)
-    for l in lege.legendHandles:
+    for l in lege.legend_handles:
         l.set_linewidth(10)
     return ax