diff --git a/Makefile.in b/Makefile.in
index 0404e2bdee6cf..dfeb735f5f1e6 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -141,6 +141,9 @@ endif
 CFG_GIT_DIR := $(CFG_SRC_DIR).git
 CFG_RELEASE = 0.7-pre
 CFG_VERSION = $(CFG_RELEASE)
+# windows exe's need numeric versions - don't use anything but
+# numbers and dots here
+CFG_VERSION_WIN = 0.7
 
 ifneq ($(wildcard $(CFG_GIT)),)
 ifneq ($(wildcard $(CFG_GIT_DIR)),)
@@ -311,6 +314,7 @@ $(foreach host,$(CFG_HOST_TRIPLES), \
 export CFG_SRC_DIR
 export CFG_BUILD_DIR
 export CFG_VERSION
+export CFG_VERSION_WIN
 export CFG_BUILD_TRIPLE
 export CFG_LLVM_ROOT
 export CFG_ENABLE_MINGW_CROSS
diff --git a/src/etc/pkg/rust.iss b/src/etc/pkg/rust.iss
index 18f358a9893d3..0375a041a39e9 100644
--- a/src/etc/pkg/rust.iss
+++ b/src/etc/pkg/rust.iss
@@ -1,4 +1,5 @@
 #define CFG_VERSION GetEnv("CFG_VERSION")
+#define CFG_VERSION_WIN GetEnv("CFG_VERSION_WIN")
 
 [Setup]
 
@@ -8,7 +9,7 @@ AppVersion={#CFG_VERSION}
 AppCopyright=Copyright (C) 2006-2013 Mozilla Foundation, MIT license
 AppPublisher=Mozilla Foundation
 AppPublisherURL=http://www.rust-lang.org
-VersionInfoVersion={#CFG_VERSION}
+VersionInfoVersion={#CFG_VERSION_WIN}
 LicenseFile=LICENSE.txt
 
 DisableWelcomePage=true