diff --git a/Makefile b/Makefile
index 16e6b32eba09181ad4f4d2d5ced4ef228955c114..c023ee96032ffc0ba44f7a8d05fcfd45834d950f 100644
--- a/Makefile
+++ b/Makefile
@@ -361,7 +361,7 @@ E = @echo
 Q = @
 endif
 
-VERSION = 0.13.0.0
+VERSION = 0.13.0-dev
 
 CPPFLAGS_NO_ARCH += $(addprefix -I, $(INCLUDES)) $(addprefix -D, $(DEFINES))
 CPPFLAGS += $(CPPFLAGS_NO_ARCH) $(ARCH_FLAGS)
diff --git a/build.yaml b/build.yaml
index b61594519812e0626e8d1f28743761e29f3bfd14..6c42ec82694e6d34b1916ea2368f7afc3edec82b 100644
--- a/build.yaml
+++ b/build.yaml
@@ -2,12 +2,12 @@
 '#2': It is used among other things to generate all of our project files.
 '#3': Please refer to the templates directory for more information.
 settings:
-  '#': The public version number of the library.
-  version:
-    major: 0
-    minor: 13
-    micro: 0
-    build: 0
+  '#1': The public version number of the library.
+  '#2': Master always has a "-dev" suffix
+  '#3': Use "-preN" suffixes to identify pre-release versions
+  '#4': Per-language overrides are possible with (eg) ruby_version security_connector_test
+  '#5': See the expand_version.py for all the quirks here
+  version: 0.13.0-dev
 filegroups:
 - name: census
   public_headers:
diff --git a/setup.py b/setup.py
index 80828a3b4a9aa3d9cc9ec033648bee0f9e676fb4..f8450a7677fefedc451ff8429e089efd0ce17107 100644
--- a/setup.py
+++ b/setup.py
@@ -54,6 +54,7 @@ sys.path.insert(0, os.path.abspath(PYTHON_STEM))
 # Break import-style to ensure we can actually find our in-repo dependencies.
 import commands
 import grpc_core_dependencies
+import grpc_version
 
 LICENSE = '3-clause BSD'
 
@@ -218,7 +219,7 @@ else:
 
 setuptools.setup(
     name='grpcio',
-    version='0.12.0b8',
+    version=grpc_version.VERSION,
     license=LICENSE,
     ext_modules=CYTHON_EXTENSION_MODULES,
     packages=list(PACKAGES),
diff --git a/src/core/surface/version.c b/src/core/surface/version.c
index 262a13f184d86e3b253c362a53f0ec2f00d4cca6..b33c99ab19d19af59a5c3820595c6a802a515d81 100644
--- a/src/core/surface/version.c
+++ b/src/core/surface/version.c
@@ -36,4 +36,4 @@
 
 #include <grpc/grpc.h>
 
-const char *grpc_version_string(void) { return "0.13.0.0"; }
+const char *grpc_version_string(void) { return "0.13.0-dev"; }
diff --git a/src/csharp/Grpc.Core/VersionInfo.cs b/src/csharp/Grpc.Core/VersionInfo.cs
index 65813909deef87d48d33ee397981fd6fa0368ea3..7124ec85d36a65876f194734a64eb8fde23ecd7c 100644
--- a/src/csharp/Grpc.Core/VersionInfo.cs
+++ b/src/csharp/Grpc.Core/VersionInfo.cs
@@ -41,6 +41,6 @@ namespace Grpc.Core
         /// <summary>
         /// Current version of gRPC C#
         /// </summary>
-        public const string CurrentVersion = "0.13.0";
+        public const string CurrentVersion = "0.13.0-dev";
     }
 }
diff --git a/src/csharp/build_packages.bat b/src/csharp/build_packages.bat
index e423545ef8cd98f48b1a6bd69590673b7cbacc8d..2c4e4e514d473f817509fb4c565e52215fca45b9 100644
--- a/src/csharp/build_packages.bat
+++ b/src/csharp/build_packages.bat
@@ -1,7 +1,7 @@
 @rem Builds gRPC NuGet packages
 
 @rem Current package versions
-set VERSION=0.13.0
+set VERSION=0.13.0-dev
 set PROTOBUF_VERSION=3.0.0-beta2
 
 @rem Packages that depend on prerelease packages (like Google.Protobuf) need to have prerelease suffix as well.
diff --git a/src/python/grpcio/grpc_version.py b/src/python/grpcio/grpc_version.py
new file mode 100644
index 0000000000000000000000000000000000000000..8a40544981fd95bc4261d95f7b81f331565636a3
--- /dev/null
+++ b/src/python/grpcio/grpc_version.py
@@ -0,0 +1,32 @@
+# Copyright 2015-2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio/grpc_version.py.template`!!!
+
+VERSION='0.13.0.dev0'
diff --git a/src/ruby/lib/grpc/version.rb b/src/ruby/lib/grpc/version.rb
index 89ff882916ca35acc617188f8a61471af0515744..e701d5847898bba5f287894a24fec8ec910823c6 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 = '0.13.0.0'
+  VERSION = '0.13.0-dev'
 end
diff --git a/templates/Makefile.template b/templates/Makefile.template
index 1a38e267a7f5611914a9e1da448821a6a0a4e795..994251421165020e3857f7beeef5eb20996529ff 100644
--- a/templates/Makefile.template
+++ b/templates/Makefile.template
@@ -276,7 +276,7 @@
   Q = @
   endif
 
-  VERSION = ${settings.version.major}.${settings.version.minor}.${settings.version.micro}.${settings.version.build}
+  VERSION = ${settings.core_version}
 
   CPPFLAGS_NO_ARCH += $(addprefix -I, $(INCLUDES)) $(addprefix -D, $(DEFINES))
   CPPFLAGS += $(CPPFLAGS_NO_ARCH) $(ARCH_FLAGS)
@@ -320,7 +320,7 @@
   ifeq ($(SYSTEM),MINGW32)
   SHARED_EXT = dll
   SHARED_PREFIX =
-  SHARED_VERSION = -${settings.version.major}
+  SHARED_VERSION = -${settings.core_version.major}
   else ifeq ($(SYSTEM),Darwin)
   SHARED_EXT = dylib
   SHARED_PREFIX = lib
@@ -1286,7 +1286,7 @@
   ifeq ($(SYSTEM),MINGW32)
   	$(Q) $(INSTALL) $(LIBDIR)/$(CONFIG)/lib${lib.name}-imp.a $(prefix)/lib/lib${lib.name}-imp.a
   else ifneq ($(SYSTEM),Darwin)
-  	$(Q) ln -sf $(SHARED_PREFIX)${lib.name}$(SHARED_VERSION).$(SHARED_EXT) $(prefix)/lib/lib${lib.name}.so.${settings.version.major}
+  	$(Q) ln -sf $(SHARED_PREFIX)${lib.name}$(SHARED_VERSION).$(SHARED_EXT) $(prefix)/lib/lib${lib.name}.so.${settings.core_version.major}
   	$(Q) ln -sf $(SHARED_PREFIX)${lib.name}$(SHARED_VERSION).$(SHARED_EXT) $(prefix)/lib/lib${lib.name}.so
   endif
   % endif
@@ -1304,7 +1304,7 @@
   ifeq ($(SYSTEM),MINGW32)
   	$(Q) $(INSTALL) $(LIBDIR)/$(CONFIG)/lib${lib.name}-imp.a $(prefix)/lib/lib${lib.name}-imp.a
   else ifneq ($(SYSTEM),Darwin)
-  	$(Q) ln -sf $(SHARED_PREFIX)${lib.name}$(SHARED_VERSION).$(SHARED_EXT) $(prefix)/lib/lib${lib.name}.so.${settings.version.major}
+  	$(Q) ln -sf $(SHARED_PREFIX)${lib.name}$(SHARED_VERSION).$(SHARED_EXT) $(prefix)/lib/lib${lib.name}.so.${settings.core_version.major}
   	$(Q) ln -sf $(SHARED_PREFIX)${lib.name}$(SHARED_VERSION).$(SHARED_EXT) $(prefix)/lib/lib${lib.name}.so
   endif
   % endif
@@ -1578,8 +1578,8 @@
   ifeq ($(SYSTEM),Darwin)
   	$(Q) ${ld} ${ldflags} -L$(LIBDIR)/$(CONFIG) -install_name $(SHARED_PREFIX)${lib.name}$(SHARED_VERSION).$(SHARED_EXT) -dynamiclib -o ${out_libbase}.$(SHARED_EXT) ${common}${libs}
   else
-  	$(Q) ${ld} ${ldflags} -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,lib${lib.name}.so.${settings.version.major} -o ${out_libbase}.$(SHARED_EXT) ${common}${libs}
-  	$(Q) ln -sf $(SHARED_PREFIX)${lib.name}$(SHARED_VERSION).$(SHARED_EXT) ${out_libbase}.so.${settings.version.major}
+  	$(Q) ${ld} ${ldflags} -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,lib${lib.name}.so.${settings.core_version.major} -o ${out_libbase}.$(SHARED_EXT) ${common}${libs}
+  	$(Q) ln -sf $(SHARED_PREFIX)${lib.name}$(SHARED_VERSION).$(SHARED_EXT) ${out_libbase}.so.${settings.core_version.major}
   	$(Q) ln -sf $(SHARED_PREFIX)${lib.name}$(SHARED_VERSION).$(SHARED_EXT) ${out_libbase}.so
   endif
   endif
diff --git a/templates/src/core/surface/version.c.template b/templates/src/core/surface/version.c.template
index 4788dc47d9f8d5227dc1aaa6d3f1982b6c696241..f2b3cfdc5893baf3ce12775ac38af41b5f433de6 100644
--- a/templates/src/core/surface/version.c.template
+++ b/templates/src/core/surface/version.c.template
@@ -38,5 +38,4 @@
   
   #include <grpc/grpc.h>
   
-  const char *grpc_version_string(void) { \
-  return "${settings.version.major}.${settings.version.minor}.${settings.version.micro}.${settings.version.build}"; }
+  const char *grpc_version_string(void) { return "${settings.core_version}"; }
diff --git a/templates/src/csharp/Grpc.Core/VersionInfo.cs.template b/templates/src/csharp/Grpc.Core/VersionInfo.cs.template
index 48197baf7d0d422c49779672fae69b098cc89134..578f01f07939a4018f5404104c42398b32d37d70 100644
--- a/templates/src/csharp/Grpc.Core/VersionInfo.cs.template
+++ b/templates/src/csharp/Grpc.Core/VersionInfo.cs.template
@@ -43,6 +43,6 @@
           /// <summary>
           /// Current version of gRPC C#
           /// </summary>
-          public const string CurrentVersion = "${settings.version.major}.${settings.version.minor}.${settings.version.micro}";
+          public const string CurrentVersion = "${settings.csharp_version}";
       }
   }
diff --git a/templates/src/csharp/build_packages.bat.template b/templates/src/csharp/build_packages.bat.template
index 847653bdcfb584566b4aec9b53a80e507078b427..b855126ae60084fdb02d554a3a2b2bbb4e5602c3 100644
--- a/templates/src/csharp/build_packages.bat.template
+++ b/templates/src/csharp/build_packages.bat.template
@@ -3,7 +3,7 @@
   @rem Builds gRPC NuGet packages
   
   @rem Current package versions
-  set VERSION=${settings.version.major}.${settings.version.minor}.${settings.version.micro}
+  set VERSION=${settings.csharp_version}
   set PROTOBUF_VERSION=3.0.0-beta2
   
   @rem Packages that depend on prerelease packages (like Google.Protobuf) need to have prerelease suffix as well.
diff --git a/templates/src/python/grpcio/grpc_version.py.template b/templates/src/python/grpcio/grpc_version.py.template
new file mode 100644
index 0000000000000000000000000000000000000000..aaacab1a5080a02919297e3417da7ac0399d3f81
--- /dev/null
+++ b/templates/src/python/grpcio/grpc_version.py.template
@@ -0,0 +1,34 @@
+%YAML 1.2
+--- |
+  # Copyright 2015-2016, Google Inc.
+  # All rights reserved.
+  #
+  # Redistribution and use in source and binary forms, with or without
+  # modification, are permitted provided that the following conditions are
+  # met:
+  #
+  #     * Redistributions of source code must retain the above copyright
+  # notice, this list of conditions and the following disclaimer.
+  #     * Redistributions in binary form must reproduce the above
+  # copyright notice, this list of conditions and the following disclaimer
+  # in the documentation and/or other materials provided with the
+  # distribution.
+  #     * Neither the name of Google Inc. nor the names of its
+  # contributors may be used to endorse or promote products derived from
+  # this software without specific prior written permission.
+  #
+  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+  # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+  # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+  # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+  # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+  # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+  # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+  # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio/grpc_version.py.template`!!!
+
+  VERSION='${settings.python_version.pep440()}'
diff --git a/templates/src/ruby/lib/grpc/version.rb.template b/templates/src/ruby/lib/grpc/version.rb.template
index 4859d2f883405cf872690a398be3d56a28a73cf8..a47d2d854894516324079693b0fa068002c40115 100644
--- a/templates/src/ruby/lib/grpc/version.rb.template
+++ b/templates/src/ruby/lib/grpc/version.rb.template
@@ -31,5 +31,5 @@
 
   # GRPC contains the General RPC module.
   module GRPC
-    VERSION = '${settings.version.major}.${settings.version.minor}.${settings.version.micro}.${settings.version.build}'
+    VERSION = '${settings.ruby_version}'
   end
diff --git a/templates/tools/doxygen/Doxyfile.include b/templates/tools/doxygen/Doxyfile.include
index 21ef8a8ecd34f744caaa7689b6331fbf76d1b230..8b0c528c1f68f5eee14b6609d5cab25c6fe0fc92 100644
--- a/templates/tools/doxygen/Doxyfile.include
+++ b/templates/tools/doxygen/Doxyfile.include
@@ -57,7 +57,7 @@ PROJECT_NAME           = "GRPC ${packagename}"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = ${settings.version.major}.${settings.version.minor}.${settings.version.micro}.${settings.version.build}
+PROJECT_NUMBER         = ${settings.core_version if packagename=='Core' else settings.cpp_version}
 
 # 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/buildgen/build-cleaner.py b/tools/buildgen/build-cleaner.py
index 37fedec6ad103a4c1e6dc7d81133f11d0b810df2..49a364412350c0aa6bb02e61c1b426ce9bc8fc29 100755
--- a/tools/buildgen/build-cleaner.py
+++ b/tools/buildgen/build-cleaner.py
@@ -38,7 +38,6 @@ import yaml
 TEST = (os.environ.get('TEST', 'false') == 'true')
 
 _TOP_LEVEL_KEYS = ['settings', 'proto_deps', 'filegroups', 'libs', 'targets', 'vspackages']
-_VERSION_KEYS = ['major', 'minor', 'micro', 'build']
 _ELEM_KEYS = [
     'name',
     'cpu_cost',
@@ -83,8 +82,6 @@ for filename in sys.argv[1:]:
   with open(filename) as f:
     js = yaml.load(f)
   js = rebuild_as_ordered_dict(js, _TOP_LEVEL_KEYS)
-  js['settings']['version'] = rebuild_as_ordered_dict(
-      js['settings']['version'], _VERSION_KEYS)
   for grp in ['filegroups', 'libs', 'targets']:
     if grp not in js: continue
     js[grp] = sorted([clean_elem(x) for x in js[grp]],
diff --git a/tools/buildgen/plugins/expand_version.py b/tools/buildgen/plugins/expand_version.py
new file mode 100755
index 0000000000000000000000000000000000000000..9f9c7c71fa7fb5482f4b4fe19a90441273514fbb
--- /dev/null
+++ b/tools/buildgen/plugins/expand_version.py
@@ -0,0 +1,94 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Buildgen .proto files list plugin.
+
+This parses the list of targets from the yaml build file, and creates
+a list called "protos" that contains all of the proto file names.
+
+"""
+
+
+import re
+
+LANGUAGES = [
+  'core', 
+  'cpp', 
+  'csharp', 
+  'node', 
+  'objc', 
+  'php',
+  'python', 
+  'ruby', 
+  ]
+
+class Version:
+
+  def __init__(self, s):
+    if '-' in s:
+      s, self.tag = s.split('-')
+    self.major, self.minor, self.patch = [int(x) for x in s.split('.')]
+
+  def __str__(self):
+    """Version string in a somewhat idiomatic style for most languages"""
+    s = '%d.%d.%d' % (self.major, self.minor, self.patch)
+    if self.tag:
+      s += '-%s' % self.tag
+    return s
+
+  def pep440(self):
+    """Version string in Python PEP440 style"""
+    s = '%d.%d.%d' % (self.major, self.minor, self.patch)
+    if self.tag:
+      # we need to translate from grpc version tags to pep440 version
+      # tags; this code is likely to be a little ad-hoc
+      if self.tag == 'dev':
+        s += '.dev0'
+      elif len(self.tag) >= 3 and self.tag[0:3] == 'pre':
+        s += 'rc%d' % int(self.tag[3:])
+      else:
+        raise Exception('Don\'t know how to translate version tag "%s" to pep440' % self.tag)
+    return s
+
+def mako_plugin(dictionary):
+  """Expand version numbers:
+     - for each language, ensure there's a language_version tag in
+       settings (defaulting to the master version tag)
+     - expand version strings to major, minor, patch, and tag
+  """
+
+  settings = dictionary['settings']
+  master_version = Version(settings['version'])
+  settings['version'] = master_version
+  for language in LANGUAGES:
+    version_tag = '%s_version' % language
+    if version_tag in settings:
+      settings[version_tag] = Version(settings[version_tag])
+    else:
+      settings[version_tag] = master_version
diff --git a/tools/doxygen/Doxyfile.c++ b/tools/doxygen/Doxyfile.c++
index cdb998d59cca0be82f421402d0b8f498ac09166b..5bc38a9aec9e89a32f8a40724db788d143663048 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         = 0.13.0.0
+PROJECT_NUMBER         = 0.13.0-dev
 
 # 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 558ec9d3947c78bd31ee9b60fe5827867a490b7e..ec71d2e9cddf717a0e00181e41b1200ccb50e740 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         = 0.13.0.0
+PROJECT_NUMBER         = 0.13.0-dev
 
 # 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.core b/tools/doxygen/Doxyfile.core
index a3b458163cda6bb0a31034c0f07c7a855563b3fd..0f22620686cf253a5666999c5b8a86b5f469b1bf 100644
--- a/tools/doxygen/Doxyfile.core
+++ b/tools/doxygen/Doxyfile.core
@@ -40,7 +40,7 @@ PROJECT_NAME           = "GRPC Core"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 0.13.0.0
+PROJECT_NUMBER         = 0.13.0-dev
 
 # 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.core.internal b/tools/doxygen/Doxyfile.core.internal
index e91b47c6f4b616c9ecff156e67d5ef03f58d5f2d..a3540778c1f8501f91ac4a6949df1985e062422b 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -40,7 +40,7 @@ PROJECT_NAME           = "GRPC Core"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 0.13.0.0
+PROJECT_NUMBER         = 0.13.0-dev
 
 # 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