diff --git a/README.md b/README.md
index cc84eccc..87be7617 100644
--- a/README.md
+++ b/README.md
@@ -21,7 +21,7 @@ phono3py repository.
 
 - Github issues is the place to discuss about phono3py issues.
 - Github pull request is the place to request merging source code.
-- Python 3.7 will be the minimum requirement soon.
+- Python 3.7 is the minimum requirement.
 - Formatting is written in `pyproject.toml`.
 - Not strictly, but VSCode's `settings.json` may be written like
 
diff --git a/conda/meta.yaml b/conda/meta.yaml
index 7616f6e6..ce18c302 100644
--- a/conda/meta.yaml
+++ b/conda/meta.yaml
@@ -26,27 +26,27 @@ build:
 
 requirements:
   build:
-    - python>=3.6
+    - python>=3.7
     - pip
-    - numpy>=1.11
+    - numpy>=1.15
     - scipy
-    - matplotlib-base>=2.0.0
+    - matplotlib-base>=2.2.2
     - pyyaml
     - h5py
-    - phonopy>=2.12,<2.13
+    - phonopy>=2.13,<2.14
     - openblas
     - libgfortran
     - spglib
 
   run:
-    - python>=3.6
+    - python>=3.7
     - pip
-    - numpy>=1.11
+    - numpy>=1.15
     - scipy
-    - matplotlib-base>=2.0.0
+    - matplotlib-base>=2.2.2
     - pyyaml
     - h5py
-    - phonopy>=2.12,<2.13
+    - phonopy>=2.13,<2.14
     - openblas
     - libgfortran
     - spglib
diff --git a/doc/_static/procedure.dot b/doc/_static/procedure.dot
index b233bf99..75d58583 100644
--- a/doc/_static/procedure.dot
+++ b/doc/_static/procedure.dot
@@ -3,7 +3,6 @@ digraph phonopy {
   "Phono3py (force-sets)" [shape = box, style = filled];
   "Phono3py (FC)" [shape = box, style = filled];
   "Phono3py (LTC)" [shape = box, style = filled];
-  "Supercell + displacements" [shape = box];
   "Force calc." [shape = octagon];
   "Force-constants calc." [shape = octagon];
 
diff --git a/doc/changelog.md b/doc/changelog.md
index 5ff0a02d..711fd350 100644
--- a/doc/changelog.md
+++ b/doc/changelog.md
@@ -2,6 +2,10 @@
 
 # Change Log
 
+## Apr-9-2022: Version 2.3.0
+
+- Maintenance release including small bug fixes.
+
 ## Feb-14-2022: Version 2.2.0
 
 - Maintenance release to follow the change of phonopy at v2.12.1.
diff --git a/doc/conf.py b/doc/conf.py
index 7868d715..bb9698bc 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -49,9 +49,9 @@ copyright = "2015, Atsushi Togo"
 # built documents.
 #
 # The short X.Y version.
-version = "2.2"
+version = "2.3"
 # The full version, including alpha/beta/rc tags.
-release = "2.2.0"
+release = "2.3.0"
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
diff --git a/doc/procedure.png b/doc/procedure.png
index ff2db850..7e005c4b 100644
Binary files a/doc/procedure.png and b/doc/procedure.png differ
diff --git a/phono3py/version.py b/phono3py/version.py
index 26c4abef..9e22741a 100644
--- a/phono3py/version.py
+++ b/phono3py/version.py
@@ -33,4 +33,4 @@
 # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
-__version__ = "2.2.0"
+__version__ = "2.3.0"
diff --git a/requirements.txt b/requirements.txt
index 562ca7de..8f8e1a11 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,4 +2,4 @@ numpy >= 1.15.0
 PyYAML
 matplotlib >= 2.2.2
 h5py
-phonopy >=2.13,<2.14
+phonopy >=2.14,<2.15
diff --git a/setup.py b/setup.py
index a790bd10..f7da1b06 100644
--- a/setup.py
+++ b/setup.py
@@ -198,7 +198,7 @@ if __name__ == "__main__":
             "matplotlib>=2.2.2",
             "h5py",
             "spglib",
-            "phonopy>=2.13,<2.14",
+            "phonopy>=2.14,<2.15",
         ],
         provides=["phono3py"],
         scripts=scripts_phono3py,