diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,10 @@
+## 0.2.4 (2022-08-26)
+
+#### Changed
+
+- Changed `for`'s callback to return `ByteStream m x`, to clarify that it is not
+  used.
+
 ## 0.2.3 (2022-08-18)
 
 #### Added
diff --git a/lib/Streaming/ByteString.hs b/lib/Streaming/ByteString.hs
--- a/lib/Streaming/ByteString.hs
+++ b/lib/Streaming/ByteString.hs
@@ -643,8 +643,11 @@
 -- | @'for' xs f@ applies @f@ to each chunk in the stream, and
 -- concatenates the resulting streams.
 --
+-- Generalised in 0.2.4 to match @streaming@: the callback's (ignored)
+-- return value can be of any type.
+--
 -- @since 0.2.3
-for :: Monad m => ByteStream m r -> (P.ByteString -> ByteStream m r) -> ByteStream m r
+for :: Monad m => ByteStream m r -> (P.ByteString -> ByteStream m x) -> ByteStream m r
 for stream f = case stream of
   Empty r -> Empty r
   Chunk bs bss -> f bs *> for bss f
diff --git a/streaming-bytestring.cabal b/streaming-bytestring.cabal
--- a/streaming-bytestring.cabal
+++ b/streaming-bytestring.cabal
@@ -1,6 +1,6 @@
 cabal-version:      >=1.10
 name:               streaming-bytestring
-version:            0.2.3
+version:            0.2.4
 synopsis:           Fast, effectful byte streams.
 description:
   This library enables fast and safe streaming of byte data, in either @Word8@ or