diff --git a/ChangeLog b/ChangeLog
index 832b6821..bce487eb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -12,6 +12,13 @@
 
 - changed the maximum number of clients supported by the server from 20 to 50
 
+TODO x64 deploy version for Windows -> change deploy script
+
+TODO client: larger sound card buffers are managed by conversion buffer, not in processintern for loop (note iSndCrdFrameSizeFactor!)
+
+TODO check why for some servers we do not get client list in server list
+
+TODO check server list registration for correct behavior
 
 
 
diff --git a/windows/deploy_windows.bat b/windows/deploy_windows.bat
index 53d414fd..16c31562 100755
--- a/windows/deploy_windows.bat
+++ b/windows/deploy_windows.bat
@@ -1,36 +1,72 @@
 @echo off
 
 rem To set up a new Qt and Visual Studio version
-rem - set environment path variable to the correct Qt bin directory (e.g. 32 bit version)
+rem - set environment path variable to the correct Qt bin directories:
+rem   - QTDIR32: points to the Qt 32 bit binaries, e.g., C:\Qt\5.10.1\msvc2015
+rem   - QTDIR64: points to the Qt 64 bin binaries, e.g., C:\Qt\5.10.1\msvc2015_64
 rem - if using Visual Studio Express version, download the redistributable (it is not automatically there)
 rem - change the Qt distribute dll names in the installer.nsi file (some contain version numbers)
 
 rem settings and check ---------------------------------------------------------
 set NSIS_PATH=%PROGRAMFILES(x86)%\NSIS
+set VS_REDIST32_EXE=vc_redist.x86.exe
+set VS_REDIST64_EXE=VC_redist.x64.exe
 
 if "%VSINSTALLDIR%" == "" goto vsenvproblem
+if "%QTDIR32%" == "" goto qtdirproblem
+if "%QTDIR64%" == "" goto qtdirproblem
+cd ..
+
+
+rem ########################## 32 bit build ####################################
+set QTDIR=%QTDIR32%
+set Path=%QTDIR32%\bin;%Path%
+rem create visual studio project file ------------------------------------------
+qmake -tp vc -spec win32-msvc
+
+rem TODO qmake seems to use the incorrect VS version to create the project file.
+rem      As a quick hack I simply replace the toolset version which seems to work.
+powershell -Command "(gc jamulus.vcxproj) -replace '<PlatformToolset>v141</PlatformToolset>', '<PlatformToolset>v140</PlatformToolset>' | Out-File -encoding ASCII jamulus.vcxproj"
+powershell -Command "(gc jamulus.vcxproj) -replace 'x64', 'Win32' | Out-File -encoding ASCII jamulus.vcxproj"
+powershell -Command "(gc jamulus.vcxproj) -replace ';WIN64', '' | Out-File -encoding ASCII jamulus.vcxproj"
+powershell -Command "(gc jamulus.vcxproj) -replace '-DWIN64 ', '' | Out-File -encoding ASCII jamulus.vcxproj"
+
+rem clean and compile solution -------------------------------------------------
+devenv Jamulus.vcxproj /Clean "Release|x86"
+devenv Jamulus.vcxproj /Build "Release|x86"
+mkdir release\x86
+copy release\Jamulus.exe release\x86\
+
+
+rem ########################## 64 bit build ####################################
+set QTDIR=%QTDIR64%
+set Path=%QTDIR64%\bin;%Path%
 
 rem create visual studio project file ------------------------------------------
-cd ..
-qmake -tp vc -spec win32-msvc
+qmake -tp vc
 
 rem TODO qmake seems to use the incorrect VS version to create the project file.
 rem      As a quick hack I simply replace the toolset version which seems to work.
 powershell -Command "(gc jamulus.vcxproj) -replace '<PlatformToolset>v141</PlatformToolset>', '<PlatformToolset>v140</PlatformToolset>' | Out-File -encoding ASCII jamulus.vcxproj"
 
 rem clean and compile solution -------------------------------------------------
-devenv Jamulus.vcxproj /Clean "Release|x86"
-devenv Jamulus.vcxproj /Build "Release|x86"
+devenv Jamulus.vcxproj /Clean "Release|x64"
+devenv Jamulus.vcxproj /Build "Release|x64"
 
-rem create installer -----------------------------------------------------------
+
+rem ########################## create installer ################################
 cd windows
 "%NSIS_PATH%\makensis.exe" installer.nsi
-
 move Jamulusinstaller.exe ../deploy/Jamulus-version-installer.exe
-
 goto endofskript
 
+
 :vsenvproblem
-echo Use the Visual Studio Command Prompt to call this skript
+echo Use the Visual Studio x86 x64 Cross Tools Command Prompt to call this skript
+goto endofskript
+
+:qtdirproblem
+echo The QTDIR32 and QTDIR64 is not set, please set these environment variables correclty before calling this script
+goto endofskript
 
 :endofskript
diff --git a/windows/installer.nsi b/windows/installer.nsi
index 30b88845..8f04714e 100755
--- a/windows/installer.nsi
+++ b/windows/installer.nsi
@@ -1,4 +1,6 @@
 ; Jamulus NSIS installer script
+!include LogicLib.nsh
+!include x64.nsh
 
 !define APP_NAME          "Jamulus"
 !define APP_EXE           "Jamulus.exe"
@@ -42,27 +44,44 @@ Section
   SetOutPath       $INSTDIR
 
   ; main application
+  ${If} ${RunningX64}
   File             "${BINARY_PATH}${APP_EXE}"
+  ${Else}
+  File             "${BINARY_PATH}x86\${APP_EXE}"
+  ${EndIf}
 
   ; QT dlls
-  File             "$%QTDIR%\bin\Qt5Core.dll"
-  File             "$%QTDIR%\bin\Qt5Gui.dll"
-  File             "$%QTDIR%\bin\Qt5Widgets.dll"
-  File             "$%QTDIR%\bin\Qt5Network.dll"
-  File             "$%QTDIR%\bin\Qt5Xml.dll"
-  File             "$%QTDIR%\bin\D3DCompiler_47.dll"
-  ; File             "$%QTDIR%\bin\icudt54.dll"
-  ; File             "$%QTDIR%\bin\icuin54.dll"
-  ; File             "$%QTDIR%\bin\icuuc54.dll"
-  File             "$%QTDIR%\bin\libEGL.dll"
-  File             "$%QTDIR%\bin\libGLESv2.dll"
+  ${If} ${RunningX64}
+  File             "$%QTDIR64%\bin\Qt5Core.dll"
+  File             "$%QTDIR64%\bin\Qt5Gui.dll"
+  File             "$%QTDIR64%\bin\Qt5Widgets.dll"
+  File             "$%QTDIR64%\bin\Qt5Network.dll"
+  File             "$%QTDIR64%\bin\Qt5Xml.dll"
+  File             "$%QTDIR64%\bin\D3DCompiler_47.dll"
+  File             "$%QTDIR64%\bin\libEGL.dll"
+  File             "$%QTDIR64%\bin\libGLESv2.dll"
+  ${Else}
+  File             "$%QTDIR32%\bin\Qt5Core.dll"
+  File             "$%QTDIR32%\bin\Qt5Gui.dll"
+  File             "$%QTDIR32%\bin\Qt5Widgets.dll"
+  File             "$%QTDIR32%\bin\Qt5Network.dll"
+  File             "$%QTDIR32%\bin\Qt5Xml.dll"
+  File             "$%QTDIR32%\bin\D3DCompiler_47.dll"
+  File             "$%QTDIR32%\bin\libEGL.dll"
+  File             "$%QTDIR32%\bin\libGLESv2.dll"
+  ${EndIf}
 
   ; other files
   File             "..\COPYING"
 
-  ; temporarily create Microsoft Visual Studio redistributable,
-  File             "${VS_REDIST_EXE}"
-  ExecWait         '"$INSTDIR\${VS_REDIST_EXE}" /q /norestart'
+  ; temporarily create Microsoft Visual Studio redistributable
+  ${If} ${RunningX64}
+  File             "$%VS_REDIST64_EXE%"
+  ExecWait         '"$INSTDIR\$%VS_REDIST64_EXE%" /q /norestart'
+  ${Else}
+  File             "$%VS_REDIST32_EXE%"
+  ExecWait         '"$INSTDIR\$%VS_REDIST32_EXE%" /q /norestart'
+  ${EndIf}
 
   ; uninstaller
   WriteUninstaller $INSTDIR\${UNINSTALL_EXE}
@@ -76,12 +95,21 @@ Section
   CreateShortCut   "$SMPROGRAMS\${APP_NAME}\${UNINSTALL_EXE}.lnk" "$INSTDIR\${UNINSTALL_EXE}"
 
   ; cleanup: remove temporary Microsoft Visual Studio redistributable executable
-  Delete           $INSTDIR\${VS_REDIST_EXE}
+  ${If} ${RunningX64}
+  Delete           $INSTDIR\$%VS_REDIST64_EXE%
+  ${Else}
+  Delete           $INSTDIR\$%VS_REDIST32_EXE%
+  ${EndIf}
 
   ; additional platform dlls
   SetOutPath       $INSTDIR\platforms
-  File             "$%QTDIR%\plugins\platforms\qwindows.dll"
-  File             "$%QTDIR%\plugins\platforms\qminimal.dll"  
+  ${If} ${RunningX64}
+  File             "$%QTDIR64%\plugins\platforms\qwindows.dll"
+  File             "$%QTDIR64%\plugins\platforms\qminimal.dll"  
+  ${Else}
+  File             "$%QTDIR32%\plugins\platforms\qwindows.dll"
+  File             "$%QTDIR32%\plugins\platforms\qminimal.dll"  
+  ${EndIf}
 
 SectionEnd
 
@@ -107,9 +135,6 @@ Delete $INSTDIR\Qt5Widgets.dll
 Delete $INSTDIR\Qt5Network.dll
 Delete $INSTDIR\Qt5Xml.dll
 Delete $INSTDIR\D3DCompiler_47.dll
-; Delete $INSTDIR\icudt54.dll
-; Delete $INSTDIR\icuin54.dll
-; Delete $INSTDIR\icuuc54.dll
 Delete $INSTDIR\libEGL.dll
 Delete $INSTDIR\libGLESv2.dll
 Delete $INSTDIR\COPYING