diff --git a/BUILD b/BUILD
index 39c23cf31231c1ae225ed07e97900b83c8c3fe5b..f3942aec58c4c08dca4aa3ee7e67c004d82e6c09 100644
--- a/BUILD
+++ b/BUILD
@@ -42,7 +42,7 @@ g_stands_for = "gentle"
 
 core_version = "3.0.0"
 
-version = "1.3.0"
+version = "1.3.1-pre1"
 
 grpc_cc_library(
     name = "gpr",
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4b296a2510aa27384b58e4c0c2e398bae23250a5..e940ef63c049b981eac7d612a1158fe7c807c5bf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -39,7 +39,7 @@
 cmake_minimum_required(VERSION 2.8)
 
 set(PACKAGE_NAME      "grpc")
-set(PACKAGE_VERSION   "1.3.0")
+set(PACKAGE_VERSION   "1.3.1-pre1")
 set(PACKAGE_STRING    "${PACKAGE_NAME} ${PACKAGE_VERSION}")
 set(PACKAGE_TARNAME   "${PACKAGE_NAME}-${PACKAGE_VERSION}")
 set(PACKAGE_BUGREPORT "https://github.com/grpc/grpc/issues/")
diff --git a/Makefile b/Makefile
index 41d47b7e3476a93b61fb52c5e3c892c1722770ba..bc28e4ecbe187a45d1a14e4874d416b9925e450b 100644
--- a/Makefile
+++ b/Makefile
@@ -420,8 +420,8 @@ Q = @
 endif
 
 CORE_VERSION = 3.0.0
-CPP_VERSION = 1.3.0
-CSHARP_VERSION = 1.3.0
+CPP_VERSION = 1.3.1-pre1
+CSHARP_VERSION = 1.3.1-pre1
 
 CPPFLAGS_NO_ARCH += $(addprefix -I, $(INCLUDES)) $(addprefix -D, $(DEFINES))
 CPPFLAGS += $(CPPFLAGS_NO_ARCH) $(ARCH_FLAGS)
diff --git a/build.yaml b/build.yaml
index d4a193cec4678c57ac4b4aedb500e87ef30ef3b7..8e44ea43aa7f624ad0b695ba547644671be1e4c5 100644
--- a/build.yaml
+++ b/build.yaml
@@ -14,7 +14,7 @@ settings:
   '#10': See the expand_version.py for all the quirks here
   core_version: 3.0.0
   g_stands_for: gentle
-  version: 1.3.0
+  version: 1.3.1-pre1
 filegroups:
 - name: census
   public_headers:
diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec
index f1c6a103bbd653263a6fd4e2aa7ab6beae96d4b5..6b70a8560b8453bfbce3ae1d80e696cd1a59e59b 100644
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@@ -37,7 +37,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'gRPC-Core'
-  version = '1.3.0'
+  version = '1.3.1-pre1'
   s.version  = version
   s.summary  = 'Core cross-platform gRPC library, written in C'
   s.homepage = 'http://www.grpc.io'
diff --git a/gRPC-ProtoRPC.podspec b/gRPC-ProtoRPC.podspec
index 14c75ac4c544d77ee555159b1e5a5effe7f5c114..73974b38bdfd4f893d91d98cab13b2c19a3b5a55 100644
--- a/gRPC-ProtoRPC.podspec
+++ b/gRPC-ProtoRPC.podspec
@@ -36,7 +36,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'gRPC-ProtoRPC'
-  version = '1.3.0'
+  version = '1.3.1-pre1'
   s.version  = version
   s.summary  = 'RPC library for Protocol Buffers, based on gRPC'
   s.homepage = 'http://www.grpc.io'
diff --git a/gRPC-RxLibrary.podspec b/gRPC-RxLibrary.podspec
index 60e8c3e93cc37bd8dbd033082d3ac341a74571bd..fbdeff5dfd4ec85a4a516dc320547873edeeafa9 100644
--- a/gRPC-RxLibrary.podspec
+++ b/gRPC-RxLibrary.podspec
@@ -36,7 +36,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'gRPC-RxLibrary'
-  version = '1.3.0'
+  version = '1.3.1-pre1'
   s.version  = version
   s.summary  = 'Reactive Extensions library for iOS/OSX.'
   s.homepage = 'http://www.grpc.io'
diff --git a/gRPC.podspec b/gRPC.podspec
index 55112253c6e9dffe42e64567a1f7a650ec8095af..738042ba869ad5e7c06c808ccb9be3e1ffb031dd 100644
--- a/gRPC.podspec
+++ b/gRPC.podspec
@@ -35,7 +35,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'gRPC'
-  version = '1.3.0'
+  version = '1.3.1-pre1'
   s.version  = version
   s.summary  = 'gRPC client library for iOS/OSX'
   s.homepage = 'http://www.grpc.io'
diff --git a/package.json b/package.json
index ce49c6380f743b03a13b3f9b0cf18fbd9f18fa35..0af43dd132f1f854676c48893cefa61892f4536b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "grpc",
-  "version": "1.3.0",
+  "version": "1.3.1-pre1",
   "author": "Google Inc.",
   "description": "gRPC Library for Node",
   "homepage": "http://www.grpc.io/",
diff --git a/package.xml b/package.xml
index 96a415957bb2469b628297c237a2d51ff74e61a7..bad95d55762f1892542cb686593f88df44c767ef 100644
--- a/package.xml
+++ b/package.xml
@@ -13,8 +13,8 @@
  <date>2017-03-01</date>
  <time>16:06:07</time>
  <version>
-  <release>1.3.0</release>
-  <api>1.3.0</api>
+  <release>1.3.1RC1</release>
+  <api>1.3.1RC1</api>
  </version>
  <stability>
   <release>beta</release>
diff --git a/src/cpp/common/version_cc.cc b/src/cpp/common/version_cc.cc
index d70a191eb69460d24e989656eaab327e03b3d0be..8d6445ed505deebce657a749a7a39c8676ee3d45 100644
--- a/src/cpp/common/version_cc.cc
+++ b/src/cpp/common/version_cc.cc
@@ -37,5 +37,5 @@
 #include <grpc++/grpc++.h>
 
 namespace grpc {
-grpc::string Version() { return "1.3.0"; }
+grpc::string Version() { return "1.3.1-pre1"; }
 }
diff --git a/src/csharp/Grpc.Core/Version.csproj.include b/src/csharp/Grpc.Core/Version.csproj.include
index 3963209f1a553ab3bd7b2864c9ea697d589f84ac..fb0fdbbabc41bdca0977543833ce19d9d43c4264 100755
--- a/src/csharp/Grpc.Core/Version.csproj.include
+++ b/src/csharp/Grpc.Core/Version.csproj.include
@@ -1,7 +1,7 @@
 <!-- This file is generated -->
 <Project>
   <PropertyGroup>
-    <GrpcCsharpVersion>1.3.0</GrpcCsharpVersion>
+    <GrpcCsharpVersion>1.3.1-pre1</GrpcCsharpVersion>
     <GoogleProtobufVersion>3.2.0</GoogleProtobufVersion>
   </PropertyGroup>
 </Project>
diff --git a/src/csharp/Grpc.Core/VersionInfo.cs b/src/csharp/Grpc.Core/VersionInfo.cs
index bdcfb914edbf35989900b3ef983ff0430e802ea6..dfe8c06e65dbd2551acaf40f3defe433aaae6bbe 100644
--- a/src/csharp/Grpc.Core/VersionInfo.cs
+++ b/src/csharp/Grpc.Core/VersionInfo.cs
@@ -48,11 +48,11 @@ namespace Grpc.Core
         /// <summary>
         /// Current <c>AssemblyFileVersion</c> of gRPC C# assemblies
         /// </summary>
-        public const string CurrentAssemblyFileVersion = "1.3.0.0";
+        public const string CurrentAssemblyFileVersion = "1.3.1.0";
 
         /// <summary>
         /// Current version of gRPC C#
         /// </summary>
-        public const string CurrentVersion = "1.3.0";
+        public const string CurrentVersion = "1.3.1-pre1";
     }
 }
diff --git a/src/csharp/build_packages_dotnetcli.bat b/src/csharp/build_packages_dotnetcli.bat
index cc9c6d11a5cf55f753c763e2d00b68ecbf762480..b9a7ed47fcd693b04cd5f739e96454404e194bc7 100755
--- a/src/csharp/build_packages_dotnetcli.bat
+++ b/src/csharp/build_packages_dotnetcli.bat
@@ -28,7 +28,7 @@
 @rem OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 @rem Current package versions
-set VERSION=1.3.0
+set VERSION=1.3.1-pre1
 
 @rem Adjust the location of nuget.exe
 set NUGET=C:\nuget\nuget.exe
diff --git a/src/csharp/build_packages_dotnetcli.sh b/src/csharp/build_packages_dotnetcli.sh
index 57e8fd4895ba45c157de2880cda6aea940e92985..defb75280b735c5f2ed5737c43553de917340bda 100755
--- a/src/csharp/build_packages_dotnetcli.sh
+++ b/src/csharp/build_packages_dotnetcli.sh
@@ -70,7 +70,7 @@ dotnet pack --configuration Release Grpc.Auth --output ../../../artifacts
 dotnet pack --configuration Release Grpc.HealthCheck --output ../../../artifacts
 dotnet pack --configuration Release Grpc.Reflection --output ../../../artifacts
 
-nuget pack Grpc.nuspec -Version "1.3.0" -OutputDirectory ../../artifacts
-nuget pack Grpc.Tools.nuspec -Version "1.3.0" -OutputDirectory ../../artifacts
+nuget pack Grpc.nuspec -Version "1.3.1-pre1" -OutputDirectory ../../artifacts
+nuget pack Grpc.Tools.nuspec -Version "1.3.1-pre1" -OutputDirectory ../../artifacts
 
 (cd ../../artifacts && zip csharp_nugets_dotnetcli.zip *.nupkg)
diff --git a/src/node/health_check/package.json b/src/node/health_check/package.json
index a63eacae987c58750fc641f16ec5e0453e065f72..e7b50362fc558b0f299b8e8bc9c371666cba3681 100644
--- a/src/node/health_check/package.json
+++ b/src/node/health_check/package.json
@@ -1,6 +1,6 @@
 {
   "name": "grpc-health-check",
-  "version": "1.3.0",
+  "version": "1.3.1-pre1",
   "author": "Google Inc.",
   "description": "Health check service for use with gRPC",
   "repository": {
@@ -15,7 +15,7 @@
     }
   ],
   "dependencies": {
-    "grpc": "^1.3.0",
+    "grpc": "^1.3.1-pre1",
     "lodash": "^3.9.3",
     "google-protobuf": "^3.0.0"
   },
diff --git a/src/node/tools/package.json b/src/node/tools/package.json
index a31880beb69ab8cf18ce3ed3944303d376207ef5..9fefd433d553912583f17cb54a7ca7394c22714a 100644
--- a/src/node/tools/package.json
+++ b/src/node/tools/package.json
@@ -1,6 +1,6 @@
 {
   "name": "grpc-tools",
-  "version": "1.3.0",
+  "version": "1.3.1-pre1",
   "author": "Google Inc.",
   "description": "Tools for developing with gRPC on Node.js",
   "homepage": "http://www.grpc.io/",
diff --git a/src/objective-c/!ProtoCompiler-gRPCPlugin.podspec b/src/objective-c/!ProtoCompiler-gRPCPlugin.podspec
index b2827f806027b5d43329c14776014caf6f7dcf1d..a0df2597e22ceb574a225ab11f784edb801925a4 100644
--- a/src/objective-c/!ProtoCompiler-gRPCPlugin.podspec
+++ b/src/objective-c/!ProtoCompiler-gRPCPlugin.podspec
@@ -42,7 +42,7 @@ Pod::Spec.new do |s|
   # exclamation mark ensures that other "regular" pods will be able to find it as it'll be installed
   # before them.
   s.name     = '!ProtoCompiler-gRPCPlugin'
-  v = '1.3.0'
+  v = '1.3.1-pre1'
   s.version  = v
   s.summary  = 'The gRPC ProtoC plugin generates Objective-C files from .proto services.'
   s.description = <<-DESC
diff --git a/src/objective-c/GRPCClient/private/version.h b/src/objective-c/GRPCClient/private/version.h
index 9789d1243d7e0f31eeffd23a617a8080cb0dc0d3..83fe9e46d9c74c3aa133f80abef527110cee7504 100644
--- a/src/objective-c/GRPCClient/private/version.h
+++ b/src/objective-c/GRPCClient/private/version.h
@@ -38,4 +38,4 @@
 // `tools/buildgen/generate_projects.sh`.
 
 
-#define GRPC_OBJC_VERSION_STRING @"1.3.0"
+#define GRPC_OBJC_VERSION_STRING @"1.3.1-pre1"
diff --git a/src/php/composer.json b/src/php/composer.json
index 2b140077cc5ed9ddbb4e508d6bce036b8b161f6f..0084b94950231bbf2fee151049d2fa1ba38a8aaa 100644
--- a/src/php/composer.json
+++ b/src/php/composer.json
@@ -2,7 +2,7 @@
   "name": "grpc/grpc-dev",
   "description": "gRPC library for PHP - for Developement use only",
   "license": "BSD-3-Clause",
-  "version": "1.3.0",
+  "version": "1.3.1",
   "require": {
     "php": ">=5.5.0",
     "google/protobuf": "^v3.1.0"
diff --git a/src/python/grpcio/grpc_version.py b/src/python/grpcio/grpc_version.py
index a15756a7210306f86e16ac7339e788cb2d375178..c0422372e80d7ec1e389c9c29f8dbc4f4cfd6ff6 100644
--- a/src/python/grpcio/grpc_version.py
+++ b/src/python/grpcio/grpc_version.py
@@ -29,4 +29,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio/grpc_version.py.template`!!!
 
-VERSION='1.3.0'
+VERSION='1.3.1rc1'
diff --git a/src/python/grpcio_health_checking/grpc_version.py b/src/python/grpcio_health_checking/grpc_version.py
index df1e4af31dc87574ba13668f948fb15522933602..da7546381f94d208a5e0d48e50747c6a95b89297 100644
--- a/src/python/grpcio_health_checking/grpc_version.py
+++ b/src/python/grpcio_health_checking/grpc_version.py
@@ -29,4 +29,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio_health_checking/grpc_version.py.template`!!!
 
-VERSION='1.3.0'
+VERSION='1.3.1rc1'
diff --git a/src/python/grpcio_reflection/grpc_version.py b/src/python/grpcio_reflection/grpc_version.py
index a102538799e85efdbf9ac676495104340d37562b..367773f088967ea1917842a1e0f4310bcd05865e 100644
--- a/src/python/grpcio_reflection/grpc_version.py
+++ b/src/python/grpcio_reflection/grpc_version.py
@@ -29,4 +29,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio_reflection/grpc_version.py.template`!!!
 
-VERSION='1.3.0'
+VERSION='1.3.1rc1'
diff --git a/src/python/grpcio_tests/grpc_version.py b/src/python/grpcio_tests/grpc_version.py
index 5cce3ae7efa5b117cdc8223563269ffa6e069b56..ce78dc93f226755ef7337b3ccab0b5a33ca11f2f 100644
--- a/src/python/grpcio_tests/grpc_version.py
+++ b/src/python/grpcio_tests/grpc_version.py
@@ -29,4 +29,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio_tests/grpc_version.py.template`!!!
 
-VERSION='1.3.0'
+VERSION='1.3.1rc1'
diff --git a/src/ruby/lib/grpc/version.rb b/src/ruby/lib/grpc/version.rb
index 26c452e4a709e0965406de1c036b5b004842a5bb..b6825fa11915680ce50ac5ff2d8e0c204b9942da 100644
--- a/src/ruby/lib/grpc/version.rb
+++ b/src/ruby/lib/grpc/version.rb
@@ -29,5 +29,5 @@
 
 # GRPC contains the General RPC module.
 module GRPC
-  VERSION = '1.3.0'
+  VERSION = '1.3.1.pre1'
 end
diff --git a/src/ruby/tools/version.rb b/src/ruby/tools/version.rb
index c643a2225b06c7295fb2f4a7444f88652aa4d459..e02b87e5da0d6e59e4a378b9a89ec4d59a1fd31e 100644
--- a/src/ruby/tools/version.rb
+++ b/src/ruby/tools/version.rb
@@ -29,6 +29,6 @@
 
 module GRPC
   module Tools
-    VERSION = '1.3.0'
+    VERSION = '1.3.1.pre1'
   end
 end
diff --git a/tools/distrib/python/grpcio_tools/grpc_version.py b/tools/distrib/python/grpcio_tools/grpc_version.py
index 71ec92508b76140af2b4ebbcf75fd73e615205c6..ca1d268f890457d501df58414347f034534f5f1d 100644
--- a/tools/distrib/python/grpcio_tools/grpc_version.py
+++ b/tools/distrib/python/grpcio_tools/grpc_version.py
@@ -29,4 +29,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/tools/distrib/python/grpcio_tools/grpc_version.py.template`!!!
 
-VERSION='1.3.0'
+VERSION='1.3.1rc1'
diff --git a/tools/doxygen/Doxyfile.c++ b/tools/doxygen/Doxyfile.c++
index 26e6e09fed07e9e737952e1122d3872857caeff8..debd50638f0b0089d04d03da8db93acd26ef5701 100644
--- a/tools/doxygen/Doxyfile.c++
+++ b/tools/doxygen/Doxyfile.c++
@@ -40,7 +40,7 @@ PROJECT_NAME           = "GRPC C++"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 1.3.0
+PROJECT_NUMBER         = 1.3.1-pre1
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a
diff --git a/tools/doxygen/Doxyfile.c++.internal b/tools/doxygen/Doxyfile.c++.internal
index 5eab7e99d1f6fcc1dcd03a93d877bf043cad2e69..7064e6641bad5f23ff2f414315d8c33fdc7856bd 100644
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@@ -40,7 +40,7 @@ PROJECT_NAME           = "GRPC C++"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 1.3.0
+PROJECT_NUMBER         = 1.3.1-pre1
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a