diff --git a/README.md b/README.md
index 7eefa15..ed61c25 100644
--- a/README.md
+++ b/README.md
@@ -7,9 +7,9 @@ More thorough docs are available at [http://jparyani.github.io/pycapnp/](http://
 First you need a system-wide installation of the Cap'n Proto C++ library == 0.4.x. Follow the [official installation docs](http://kentonv.github.io/capnproto/install.html) or for the lazy:
 
 ```bash
-curl -O http://capnproto.org/capnproto-c++-0.3.0.tar.gz
-tar zxf capnproto-c++-0.3.0.tar.gz
-cd capnproto-c++-0.3.0
+curl -O http://capnproto.org/capnproto-c++-0.4.0.tar.gz
+tar zxf capnproto-c++-0.4.0.tar.gz
+cd capnproto-c++-0.4.0
 ./configure
 make -j6 check
 sudo make install
diff --git a/docs/install.rst b/docs/install.rst
index 643ab3e..c4720d5 100644
--- a/docs/install.rst
+++ b/docs/install.rst
@@ -8,9 +8,9 @@ C++ Cap'n Proto Library
 
 You need to install the C++ Cap'n Proto library first. It requires a C++ compiler with C++11 support, such as GCC 4.7+ or Clang 3.2+. Follow installation docs at `http://kentonv.github.io/capnproto/install.html <http://kentonv.github.io/capnproto/install.html>`_, or if you're feeling lazy, you can run the commands below::
 
-    curl -O http://capnproto.org/capnproto-c++-0.3.0.tar.gz
-    tar zxf capnproto-c++-0.3.0.tar.gz
-    cd capnproto-c++-0.3.0
+    curl -O http://capnproto.org/capnproto-c++-0.4.0.tar.gz
+    tar zxf capnproto-c++-0.4.0.tar.gz
+    cd capnproto-c++-0.4.0
     ./configure
     make -j6 check
     sudo make install