Prepare v4.2.1.
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 6ebd203..ef1a8a1 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -1,3 +1,11 @@
+v4.2.1 (UNRELEASED)
+===================
+
+- Handle ``__missing__()`` not storing cache items.
+
+- Clean up ``__missing__()`` example.
+
+
 v4.2.0 (2020-12-10)
 ===================
 
diff --git a/README.rst b/README.rst
index 6126d49..9fd8c36 100644
--- a/README.rst
+++ b/README.rst
@@ -85,7 +85,7 @@
 License
 ------------------------------------------------------------------------
 
-Copyright (c) 2014-2020 Thomas Kemmer.
+Copyright (c) 2014-2021 Thomas Kemmer.
 
 Licensed under the `MIT License`_.
 
diff --git a/cachetools/__init__.py b/cachetools/__init__.py
index 4be1ebe..2e66e20 100644
--- a/cachetools/__init__.py
+++ b/cachetools/__init__.py
@@ -21,4 +21,4 @@
     'cachedmethod'
 )
 
-__version__ = '4.2.0'
+__version__ = '4.2.1'
diff --git a/docs/conf.py b/docs/conf.py
index 92dda3a..9efbd40 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -9,7 +9,7 @@
 
 
 project = 'cachetools'
-copyright = '2014-2020 Thomas Kemmer'
+copyright = '2014-2021 Thomas Kemmer'
 version = get_version()
 release = version
 
diff --git a/setup.cfg b/setup.cfg
index e7af1ee..5e40883 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,6 +1,6 @@
 [metadata]
 name = cachetools
-version = 4.2.0
+version = 4.2.1
 url = https://github.com/tkem/cachetools/
 author = Thomas Kemmer
 author_email = tkemmer@computer.org