diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # composition-prelude
 
+# 2.0.2.1
+
+  * Polish documentation
+
 # 2.0.2.0
 
   * Add `$.`
diff --git a/composition-prelude.cabal b/composition-prelude.cabal
--- a/composition-prelude.cabal
+++ b/composition-prelude.cabal
@@ -1,6 +1,6 @@
 cabal-version: 1.18
 name: composition-prelude
-version: 2.0.2.0
+version: 2.0.2.1
 license: BSD3
 license-file: LICENSE
 copyright: Copyright: (c) 2017-2018 Vanessa McHale
diff --git a/src/Control/Composition.hs b/src/Control/Composition.hs
--- a/src/Control/Composition.hs
+++ b/src/Control/Composition.hs
@@ -91,6 +91,7 @@
 both :: (a -> b) -> (a, a) -> (b, b)
 both = join (***)
 
+-- | @since 2.0.1.0
 dup :: a -> (a, a)
 dup = join (,)
 
@@ -103,6 +104,8 @@
 -- to
 --
 -- > between .$ (char '"')
+--
+-- @since 2.0.2.0
 (.$) :: Monad m => m (m a) -> m a
 (.$) = join