diff --git a/Tools/msi/README.txt b/Tools/msi/README.txt
index 25dcf32..7023b61 100644
--- a/Tools/msi/README.txt
+++ b/Tools/msi/README.txt
@@ -62,10 +62,14 @@
 Building the Installer
 ======================
 
+Before building the installer, download extra build dependencies using
+Tools\msi\get_externals.bat. (Note that this is in addition to the
+similarly named file in PCBuild.)
+
 For testing, the installer should be built with the Tools/msi/build.bat
 script:
 
-    build.bat [-x86] [-x64] [--doc]
+    build.bat [-x86] [-x64] [--doc] [--test-marker] [--pack]
 
 This script will build the required configurations of Python and
 generate an installer layout in PCBuild/(win32|amd64)/en-us.
@@ -80,8 +84,13 @@
 also set %HTMLHELP% to the Html Help Compiler (hhc.exe), or put HHC on
 your PATH or in externals/.
 
-If WiX is not found on your system, it will be automatically downloaded
-and extracted to the externals/ directory.
+Specify --test-marker to build an installer that works side-by-side with
+an official Python release. All registry keys and install locations will
+include an extra marker to avoid overwriting files. This marker is
+currently an 'x' prefix, but may change at any time.
+
+Specify --pack to build an installer that does not require all MSIs to
+be available alongside. This takes longer, but is easier to share.
 
 
 For an official release, the installer should be built with the
@@ -175,6 +184,38 @@
     When true, rebuilds all of the MSIs making up the layout. Defaults to
     true.
 
+Uploading the Installer
+=======================
+
+For official releases, the uploadrelease.bat script should be used.
+
+You will require PuTTY so that plink.exe and pscp.exe can be used, and your
+SSH key can be activated in pageant.exe. PuTTY should be either on your path
+or in %ProgramFiles(x86)%\PuTTY.
+
+To include signatures for each uploaded file, you will need gpg2.exe on your
+path or have run get_externals.bat. You may also need to "gpg2.exe --import"
+your key before running the upload script.
+
+    uploadrelease.bat --host <host> --user <username> [--dry-run] [--no-gpg]
+
+The host is the URL to the server. This can be provided by the Release
+Manager. You should be able to SSH to this address.
+
+The username is your own username, which you have permission to SSH into
+the server containing downloads.
+
+Use --dry-run to display the generated upload commands without executing
+them. Signatures for each file will be generated but not uploaded unless
+--no-gpg is also passed.
+
+Use --no-gpg to suppress signature generation and upload.
+
+The default target directory (which appears in uploadrelease.proj) is
+correct for official Python releases, but may be overridden with
+--target <path> for other purposes. This path should generally not include
+any version specifier, as that will be added automatically.
+
 Modifying the Installer
 =======================
 
@@ -298,9 +339,9 @@
 the user performing the installation.
 
 The default installation location when installing for all users is
-"%ProgramFiles%\Python 3.X" for the 64-bit interpreter and
-"%ProgramFiles(x86)%\Python 3.X" for the 32-bit interpreter. (Note that
-the latter path is equivalent to "%ProgramFiles%\Python 3.X" when
+"%ProgramFiles%\Python3X" for the 64-bit interpreter and
+"%ProgramFiles(x86)%\Python3X-32" for the 32-bit interpreter. (Note that
+the latter path is equivalent to "%ProgramFiles%\Python3X-32" when
 running a 32-bit version of Windows.) This location requires
 administrative privileges to install or later modify the installation.
 
@@ -311,6 +352,8 @@
 provides a suitable level of protection against malicious modification
 of Python's files.
 
+(Default installation locations are set in Tools\msi\bundle\bundle.wxs.)
+
 Within this install directory is the following approximate layout:
 
 .\python[w].exe The core executable files
@@ -487,6 +530,6 @@
 created by the installer, as well as __pycache__ folders that are
 explicitly handled by the installer. Python packages installed later
 using a tool like pip will not be removed. Some components may be
-installed by other installers (such as the MSVCRT) and these will not be
-removed if another product has a dependency on them.
+installed by other installers and these will not be removed if another
+product has a dependency on them.
 
diff --git a/Tools/msi/build.bat b/Tools/msi/build.bat
index 5f53a1b..b11579b 100644
--- a/Tools/msi/build.bat
+++ b/Tools/msi/build.bat
@@ -19,6 +19,8 @@
 
 if not defined BUILDX86 if not defined BUILDX64 (set BUILDX86=1) && (set BUILDX64=1)
 
+call "%D%get_externals.bat"
+
 call "%PCBUILD%env.bat" x86
 
 if defined BUILDX86 (
@@ -48,12 +50,10 @@
 )
 
 if defined BUILDX86 (
-    "%PCBUILD%win32\python.exe" "%D%get_wix.py"
     msbuild %BUILD_CMD%
     if errorlevel 1 goto :eof
 )
 if defined BUILDX64 (
-    "%PCBUILD%amd64\python.exe" "%D%get_wix.py"
     msbuild /p:Platform=x64 %BUILD_CMD%
     if errorlevel 1 goto :eof
 )
diff --git a/Tools/msi/buildrelease.bat b/Tools/msi/buildrelease.bat
index ca08df8..fc7cb9f 100644
--- a/Tools/msi/buildrelease.bat
+++ b/Tools/msi/buildrelease.bat
@@ -29,6 +29,7 @@
 
 set D=%~dp0
 set PCBUILD=%D%..\..\PCBuild\
+set EXTERNALS=%D%..\..\externals\windows-installer\
 
 set BUILDX86=
 set BUILDX64=
@@ -59,12 +60,15 @@
 
 if not defined BUILDX86 if not defined BUILDX64 (set BUILDX86=1) && (set BUILDX64=1)
 
+call "%D%get_externals.bat"
+
 :builddoc
 if "%SKIPBUILD%" EQU "1" goto skipdoc
 if "%SKIPDOC%" EQU "1" goto skipdoc
 
 if not defined PYTHON where py -q || echo Cannot find py on path and PYTHON is not set. && exit /B 1
 if not defined SPHINXBUILD where sphinx-build -q || echo Cannot find sphinx-build on path and SPHINXBUILD is not set. && exit /B 1
+
 call "%D%..\..\doc\make.bat" htmlhelp
 if errorlevel 1 goto :eof
 :skipdoc
@@ -73,7 +77,7 @@
 
 where dlltool /q && goto skipdlltoolsearch
 set _DLLTOOL_PATH=
-where /R "%D%..\..\externals" dlltool > "%TEMP%\dlltool.loc" 2> nul && set /P _DLLTOOL_PATH= < "%TEMP%\dlltool.loc" & del "%TEMP%\dlltool.loc" 
+where /R "%EXTERNALS%\" dlltool > "%TEMP%\dlltool.loc" 2> nul && set /P _DLLTOOL_PATH= < "%TEMP%\dlltool.loc" & del "%TEMP%\dlltool.loc" 
 if not exist "%_DLLTOOL_PATH%" echo Cannot find binutils on PATH or in external && exit /B 1
 for %%f in (%_DLLTOOL_PATH%) do set PATH=%PATH%;%%~dpf
 set _DLLTOOL_PATH=
@@ -170,8 +174,6 @@
     @echo off
 )
 
-"%BUILD%python.exe" "%D%get_wix.py"
-
 set BUILDOPTS=/p:Platform=%1 /p:BuildForRelease=true /p:DownloadUrl=%DOWNLOAD_URL% /p:DownloadUrlBase=%DOWNLOAD_URL_BASE% /p:ReleaseUri=%RELEASE_URI%
 if "%PGO%" NEQ "" set BUILDOPTS=%BUILDOPTS% /p:PGOBuildPath=%BUILD%
 msbuild "%D%bundle\releaselocal.wixproj" /t:Rebuild %BUILDOPTS% %CERTOPTS% /p:RebuildAll=true
diff --git a/Tools/msi/get_externals.bat b/Tools/msi/get_externals.bat
new file mode 100644
index 0000000..4ead75e
--- /dev/null
+++ b/Tools/msi/get_externals.bat
@@ -0,0 +1,27 @@
+@echo off
+setlocal
+rem Simple script to fetch source for external tools
+
+where /Q svn
+if ERRORLEVEL 1 (
+    echo.svn.exe must be on your PATH to get external tools.
+    echo.Try TortoiseSVN (http://tortoisesvn.net/^) and be sure to check the
+    echo.command line tools option.
+    popd
+    exit /b 1
+)
+
+if not exist "%~dp0..\..\externals" mkdir "%~dp0..\..\externals"
+pushd "%~dp0..\..\externals"
+
+if "%SVNROOT%"=="" set SVNROOT=http://svn.python.org/projects/external/
+
+if not exist "windows-installer\.svn" (
+    echo.Checking out installer dependencies to %CD%\windows-installer
+    svn co %SVNROOT%windows-installer
+) else (
+    echo.Updating installer dependencies in %CD%\windows-installer
+    svn up windows-installer
+)
+
+popd
diff --git a/Tools/msi/get_wix.py b/Tools/msi/get_wix.py
deleted file mode 100644
index db14156..0000000
--- a/Tools/msi/get_wix.py
+++ /dev/null
@@ -1,49 +0,0 @@
-'''
-Downloads and extracts WiX to a local directory
-'''
-
-__author__ = 'Steve Dower <steve.dower@microsoft.com>'
-
-import io
-import os
-import sys
-
-from pathlib import Path
-from subprocess import Popen
-from zipfile import ZipFile
-
-EXTERNALS_DIR = None
-for p in (Path.cwd() / __file__).parents:
-    if any(p.glob("PCBuild/*.vcxproj")):
-        EXTERNALS_DIR = p / "externals"
-        break
-
-if not EXTERNALS_DIR:
-    print("Cannot find project root")
-    sys.exit(1)
-
-WIX_BINARIES_ZIP = 'http://wixtoolset.org/downloads/v3.10.0.1823/wix310-binaries.zip'
-TARGET_BIN_ZIP = EXTERNALS_DIR / "wix.zip"
-TARGET_BIN_DIR = EXTERNALS_DIR / "wix"
-
-POWERSHELL_COMMAND = "[IO.File]::WriteAllBytes('{}', (Invoke-WebRequest {} -UseBasicParsing).Content)"
-
-if __name__ == '__main__':
-    if TARGET_BIN_DIR.exists() and any(TARGET_BIN_DIR.glob("*")):
-        print('WiX is already installed')
-        sys.exit(0)
-
-    try:
-        TARGET_BIN_DIR.mkdir()
-    except FileExistsError:
-        pass
-
-    print('Downloading WiX to', TARGET_BIN_ZIP)
-    p = Popen(["powershell.exe", "-Command", POWERSHELL_COMMAND.format(TARGET_BIN_ZIP, WIX_BINARIES_ZIP)])
-    p.wait()
-    print('Extracting WiX to', TARGET_BIN_DIR)
-    with ZipFile(str(TARGET_BIN_ZIP)) as z:
-        z.extractall(str(TARGET_BIN_DIR))
-    TARGET_BIN_ZIP.unlink()
-
-    print('Extracted WiX')
diff --git a/Tools/msi/msi.props b/Tools/msi/msi.props
index 1e2d3e2..01a81b4 100644
--- a/Tools/msi/msi.props
+++ b/Tools/msi/msi.props
@@ -53,7 +53,7 @@
         <OutputPath Condition="!HasTrailingSlash($(OutputPath))">$(OutputPath)\</OutputPath>
         <OutDir>$(OutputPath)</OutDir>
         <ReuseCabinetCache>true</ReuseCabinetCache>
-        <CRTRedist Condition="'$(CRTRedist)' == ''">$(ExternalsDir)\redist</CRTRedist>
+        <CRTRedist Condition="'$(CRTRedist)' == ''">$(ExternalsDir)\windows-installer\redist</CRTRedist>
         <CRTRedist Condition="!Exists($(CRTRedist))"></CRTRedist>
         <DocFilename>python$(MajorVersionNumber)$(MinorVersionNumber)$(MicroVersionNumber)$(ReleaseLevelName).chm</DocFilename>
 
diff --git a/Tools/msi/uploadrelease.bat b/Tools/msi/uploadrelease.bat
index 7967637..4e319ce 100644
--- a/Tools/msi/uploadrelease.bat
+++ b/Tools/msi/uploadrelease.bat
@@ -8,6 +8,7 @@
 set USER=
 set TARGET=
 set DRYRUN=false
+set NOGPG=
 
 :CheckOpts
 if "%1" EQU "-h" goto Help
@@ -18,6 +19,7 @@
 if "%1" EQU "-t" (set TARGET=%~2) && shift && shift && goto CheckOpts
 if "%1" EQU "--target" (set TARGET=%~2) && shift && shift && goto CheckOpts
 if "%1" EQU "--dry-run" (set DRYRUN=true) && shift && goto CheckOpts
+if "%1" EQU "--no-gpg" (set NOGPG=true) && shift && goto CheckOpts
 
 if not defined PLINK where plink > "%TEMP%\plink.loc" 2> nul && set /P PLINK= < "%TEMP%\plink.loc" & del "%TEMP%\plink.loc"
 if not defined PLINK where /R "%ProgramFiles(x86)%\PuTTY" plink > "%TEMP%\plink.loc" 2> nul && set /P PLINK= < "%TEMP%\plink.loc" & del "%TEMP%\plink.loc"
@@ -31,10 +33,15 @@
 if not defined PSCP echo Cannot locate pscp.exe & exit /B 1
 echo Found pscp.exe at %PSCP%
 
-if not defined GPG where gpg2 > "%TEMP%\gpg.loc" 2> nul && set /P GPG= < "%TEMP%\gpg.loc" & del "%TEMP%\gpg.loc"
-if not defined GPG where /R "%PCBUILD%..\externals" gpg2 > "%TEMP%\gpg.loc" 2> nul && set /P GPG= < "%TEMP%\gpg.loc" & del "%TEMP%\gpg.loc"
-if not defined GPG echo Cannot locate gpg2.exe. Signatures will not be uploaded & pause
-echo Found gpg2.exe at %GPG%
+if defined NOGPG (
+    set GPG=
+    echo Skipping GPG signature generation because of --no-gpg
+) else  (
+    if not defined GPG where gpg2 > "%TEMP%\gpg.loc" 2> nul && set /P GPG= < "%TEMP%\gpg.loc" & del "%TEMP%\gpg.loc"
+    if not defined GPG where /R "%PCBUILD%..\externals\windows-installer" gpg2 > "%TEMP%\gpg.loc" 2> nul && set /P GPG= < "%TEMP%\gpg.loc" & del "%TEMP%\gpg.loc"
+    if not defined GPG echo Cannot locate gpg2.exe. Signatures will not be uploaded & pause
+    echo Found gpg2.exe at %GPG%
+)
 
 call "%PCBUILD%env.bat" > nul 2> nul
 pushd "%D%"
diff --git a/Tools/msi/wix.props b/Tools/msi/wix.props
index 35492f9..fbb2d10 100644
--- a/Tools/msi/wix.props
+++ b/Tools/msi/wix.props
@@ -4,9 +4,9 @@
   
   <PropertyGroup>
     <WixInstallPath Condition="'$(WixInstallPath)' == '' and Exists('$(MSBuildThisFileDirectory)\Wix')">$(MSBuildThisFileDirectory)\Wix\</WixInstallPath>
-    <WixInstallPath Condition="'$(WixInstallPath)' == '' and Exists('$(ExternalsDir)\Wix')">$(ExternalsDir)\Wix\</WixInstallPath>
-    <WixInstallPath Condition="'$(WixInstallPath)' == ''">$(Registry:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Installer XML\3.9@InstallRoot)</WixInstallPath>
-    <WixInstallPath Condition="'$(WixInstallPath)' == ''">$(Registry:HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows Installer XML\3.9@InstallRoot)</WixInstallPath>
+    <WixInstallPath Condition="'$(WixInstallPath)' == '' and Exists('$(ExternalsDir)\windows-installer\wix')">$(ExternalsDir)\windows-installer\wix\</WixInstallPath>
+    <WixInstallPath Condition="'$(WixInstallPath)' == ''">$(Registry:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Installer XML\3.10@InstallRoot)</WixInstallPath>
+    <WixInstallPath Condition="'$(WixInstallPath)' == ''">$(Registry:HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows Installer XML\3.10@InstallRoot)</WixInstallPath>
     <WixTargetsPath>$(WixInstallPath)\Wix.targets</WixTargetsPath>
   </PropertyGroup>
 </Project>
\ No newline at end of file