diff --git a/doc/lambda2.adoc b/doc/lambda2.adoc
index d766f97..d65c0e9 100644
--- a/doc/lambda2.adoc
+++ b/doc/lambda2.adoc
@@ -14,6 +14,7 @@ Peter Dimov
 :leveloffset: +1
 
 include::lambda2/overview.adoc[]
+include::lambda2/changelog.adoc[]
 include::lambda2/reference.adoc[]
 include::lambda2/copyright.adoc[]
 
diff --git a/doc/lambda2/changelog.adoc b/doc/lambda2/changelog.adoc
new file mode 100644
index 0000000..6c23295
--- /dev/null
+++ b/doc/lambda2/changelog.adoc
@@ -0,0 +1,14 @@
+////
+Copyright 2021 Peter Dimov
+Distributed under the Boost Software License, Version 1.0.
+https://www.boost.org/LICENSE_1_0.txt
+////
+
+[#changelog]
+# Revision History
+:idprefix:
+
+## Changes in 1.78.0
+
+* Added special cases in `operator<<` and `operator>>` when
+  the first argument is a stream, to allow `std::cout << _1`.
diff --git a/doc/lambda2/overview.adoc b/doc/lambda2/overview.adoc
index 6c2c586..1324e49 100644
--- a/doc/lambda2/overview.adoc
+++ b/doc/lambda2/overview.adoc
@@ -66,7 +66,7 @@ None. A single, self-contained header.
 ## Supported Compilers
 
 * GCC 5 or later with `-std=c++14` or above
-* Clang 3.5 or later with `-std=c++14` or above
+* Clang 3.9 or later with `-std=c++14` or above
 * Visual Studio 2015, 2017, 2019
 
 Tested on https://github.com/boostorg/lambda2/actions[Github Actions] and