diff --git a/bitcoin-qt.pro b/bitcoin-qt.pro
index 66b53c23..2b980ba8 100644
--- a/bitcoin-qt.pro
+++ b/bitcoin-qt.pro
@@ -1,6 +1,6 @@
 TEMPLATE = app
 TARGET =
-VERSION = 0.5.1
+VERSION = 0.5.99
 INCLUDEPATH += src src/json src/qt
 DEFINES += QT_GUI BOOST_THREAD_USE_LIB
 CONFIG += no_include_pwd
diff --git a/doc/README b/doc/README
index 5e0f8ee1..d8453a4d 100644
--- a/doc/README
+++ b/doc/README
@@ -1,4 +1,4 @@
-Bitcoin 0.5.1 BETA
+Bitcoin 0.5.99 BETA
 
 Copyright (c) 2009-2011 Bitcoin Developers
 Distributed under the MIT/X11 software license, see the accompanying
diff --git a/doc/README_windows.txt b/doc/README_windows.txt
index d237615f..f3e9811a 100644
--- a/doc/README_windows.txt
+++ b/doc/README_windows.txt
@@ -1,4 +1,4 @@
-Bitcoin 0.5.1 BETA
+Bitcoin 0.5.99 BETA
 
 Copyright (c) 2009-2011 Bitcoin Developers
 Distributed under the MIT/X11 software license, see the accompanying
diff --git a/share/setup.nsi b/share/setup.nsi
index 0c0fa048..eb7a9bc6 100644
--- a/share/setup.nsi
+++ b/share/setup.nsi
@@ -5,7 +5,7 @@ SetCompressor /SOLID lzma
 
 # General Symbol Definitions
 !define REGKEY "SOFTWARE\$(^Name)"
-!define VERSION 0.5.1
+!define VERSION 0.5.99
 !define COMPANY "Bitcoin project"
 !define URL http://www.bitcoin.org/
 
@@ -45,13 +45,13 @@ Var StartMenuGroup
 !insertmacro MUI_LANGUAGE English
 
 # Installer attributes
-OutFile bitcoin-0.5.1-win32-setup.exe
+OutFile bitcoin-0.5.99-win32-setup.exe
 InstallDir $PROGRAMFILES\Bitcoin
 CRCCheck on
 XPStyle on
 BrandingText " "
 ShowInstDetails show
-VIProductVersion 0.5.1.0
+VIProductVersion 0.5.99.0
 VIAddVersionKey ProductName Bitcoin
 VIAddVersionKey ProductVersion "${VERSION}"
 VIAddVersionKey CompanyName "${COMPANY}"
diff --git a/src/serialize.h b/src/serialize.h
index 78cff43d..efa59808 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -60,7 +60,7 @@ class CDataStream;
 class CAutoFile;
 static const unsigned int MAX_SIZE = 0x02000000;
 
-static const int VERSION = 50100;
+static const int VERSION = 59900;
 static const char* pszSubVer = "";
 static const bool VERSION_IS_BETA = true;