diff --git a/README b/README
index 1324c7c11c..356a350e9a 100644
--- a/README
+++ b/README
@@ -35,9 +35,13 @@ Second, there are a number of prerequisites for building a Xen source
 release. Make sure you have all the following installed, either by
 visiting the project webpage or installing a pre-built package
 provided by your OS distributor:
-    * GCC v4.1 or later
+    * GCC
+      - For x86 4.1.2_20070115 or later
+      - For ARM 4.8 or later
     * GNU Make
-    * GNU Binutils
+    * GNU Binutils:
+      - For x86 2.16.91.0.5 or later
+      - For ARM 2.24 or later
     * Development install of zlib (e.g., zlib-dev)
     * Development install of Python v2.3 or later (e.g., python-dev)
     * Development install of curses (e.g., libncurses-dev)