diff --git a/build/DotnetValidation/DotnetValidation.csproj b/build/DotnetValidation/DotnetValidation.csproj
index 1b3edc84..99293ddc 100644
--- a/build/DotnetValidation/DotnetValidation.csproj
+++ b/build/DotnetValidation/DotnetValidation.csproj
@@ -48,7 +48,7 @@
   </Choose>
 
   <ItemGroup>
-    <PackageReference Include="Antlr4" Version="4.6.6" />
+    <PackageReference Include="Antlr4" Version="4.6.7-dev" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/build/DotnetValidationJavaCodegen/DotnetValidation.csproj b/build/DotnetValidationJavaCodegen/DotnetValidation.csproj
index e23f2e3f..9e774202 100644
--- a/build/DotnetValidationJavaCodegen/DotnetValidation.csproj
+++ b/build/DotnetValidationJavaCodegen/DotnetValidation.csproj
@@ -48,7 +48,7 @@
   </Choose>
 
   <ItemGroup>
-    <PackageReference Include="Antlr4" Version="4.6.6" />
+    <PackageReference Include="Antlr4" Version="4.6.7-dev" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/build/DotnetValidationSingleTarget/DotnetValidation.csproj b/build/DotnetValidationSingleTarget/DotnetValidation.csproj
index 3ec3b5c0..30e79f3f 100644
--- a/build/DotnetValidationSingleTarget/DotnetValidation.csproj
+++ b/build/DotnetValidationSingleTarget/DotnetValidation.csproj
@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Antlr4" Version="4.6.6" />
+    <PackageReference Include="Antlr4" Version="4.6.7-dev" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/build/version.ps1 b/build/version.ps1
index dc17989e..a3157f6c 100644
--- a/build/version.ps1
+++ b/build/version.ps1
@@ -1 +1 @@
-$AntlrVersion = "4.6.6"
+$AntlrVersion = "4.6.7-dev"
diff --git a/runtime/CSharp/Antlr4.Runtime/Antlr4.Runtime.csproj b/runtime/CSharp/Antlr4.Runtime/Antlr4.Runtime.csproj
index d5788cfc..78696780 100644
--- a/runtime/CSharp/Antlr4.Runtime/Antlr4.Runtime.csproj
+++ b/runtime/CSharp/Antlr4.Runtime/Antlr4.Runtime.csproj
@@ -6,8 +6,8 @@
     <EnableDefaultNoneItems>False</EnableDefaultNoneItems>
 
     <AssemblyVersion>4.6.0.0</AssemblyVersion>
-    <FileVersion>4.6.6.0</FileVersion>
-    <InformationalVersion>4.6.6</InformationalVersion>
+    <FileVersion>4.6.7.0</FileVersion>
+    <InformationalVersion>4.6.7-dev</InformationalVersion>
     <Description>The original, highly-optimized C# runtime for ANTLR 4.</Description>
     <Copyright>Copyright © Sam Harwell 2015</Copyright>
     <Company>Tunnel Vision Laboratories, LLC</Company>
diff --git a/runtime/CSharp/Antlr4.Tool/Antlr4.Tool.csproj b/runtime/CSharp/Antlr4.Tool/Antlr4.Tool.csproj
index d2470148..9149f8cc 100644
--- a/runtime/CSharp/Antlr4.Tool/Antlr4.Tool.csproj
+++ b/runtime/CSharp/Antlr4.Tool/Antlr4.Tool.csproj
@@ -11,8 +11,8 @@
     <StartupObject />
 
     <AssemblyVersion>4.6.0.0</AssemblyVersion>
-    <FileVersion>4.6.6.0</FileVersion>
-    <InformationalVersion>4.6.6</InformationalVersion>
+    <FileVersion>4.6.7.0</FileVersion>
+    <InformationalVersion>4.6.7-dev</InformationalVersion>
     <Description>A C# port of the ANTLR 4 code generation tool.</Description>
     <Copyright>Copyright © Sam Harwell 2016</Copyright>
     <Company>Tunnel Vision Laboratories, LLC</Company>
diff --git a/runtime/CSharp/Antlr4BuildTasks/Antlr4.CodeGenerator.props b/runtime/CSharp/Antlr4BuildTasks/Antlr4.CodeGenerator.props
index 3ed1b541..ce257a92 100644
--- a/runtime/CSharp/Antlr4BuildTasks/Antlr4.CodeGenerator.props
+++ b/runtime/CSharp/Antlr4BuildTasks/Antlr4.CodeGenerator.props
@@ -9,7 +9,7 @@
     <Antlr4BuildTaskPath Condition="'$(MSBuildRuntimeType)' != 'Core'">..\tools\net40</Antlr4BuildTaskPath>
     <Antlr4BuildTaskPath Condition="'$(MSBuildRuntimeType)' == 'Core'">..\tools\netstandard</Antlr4BuildTaskPath>
     <!-- Path to the ANTLR tool itself -->
-    <Antlr4ToolPath>..\tools\antlr4-csharp-4.6.6-complete.jar</Antlr4ToolPath>
+    <Antlr4ToolPath>..\tools\antlr4-csharp-4.6.7-SNAPSHOT-complete.jar</Antlr4ToolPath>
   </PropertyGroup>
 
   <Import Project="Antlr4.CodeGenerator.DefaultItems.props" />
diff --git a/runtime/CSharp/Antlr4BuildTasks/Antlr4.CodeGenerator.targets b/runtime/CSharp/Antlr4BuildTasks/Antlr4.CodeGenerator.targets
index 4c4ffe04..c5b1a9ed 100644
--- a/runtime/CSharp/Antlr4BuildTasks/Antlr4.CodeGenerator.targets
+++ b/runtime/CSharp/Antlr4BuildTasks/Antlr4.CodeGenerator.targets
@@ -33,7 +33,7 @@
   <PropertyGroup>
     <Antlr4BuildTaskLocation Condition="'$(Antlr4BuildTaskPath)'==''">$(MSBuildBinPath)</Antlr4BuildTaskLocation>
     <Antlr4BuildTaskLocation Condition="'$(Antlr4BuildTaskPath)'!=''">$(Antlr4BuildTaskPath)</Antlr4BuildTaskLocation>
-    <Antlr4ToolLocation Condition="'$(Antlr4ToolPath)'==''">$(MSBuildBinPath)\Antlr4\antlr4-csharp-4.6.6-complete.jar</Antlr4ToolLocation>
+    <Antlr4ToolLocation Condition="'$(Antlr4ToolPath)'==''">$(MSBuildBinPath)\Antlr4\antlr4-csharp-4.6.7-SNAPSHOT-complete.jar</Antlr4ToolLocation>
     <Antlr4ToolLocation Condition="'$(Antlr4ToolPath)'!=''">$(Antlr4ToolPath)</Antlr4ToolLocation>
 
     <Antlr4JavaVendor Condition="'$(Antlr4JavaVendor)'==''">JavaSoft</Antlr4JavaVendor>
diff --git a/runtime/CSharp/Antlr4BuildTasks/Antlr4BuildTasks.csproj b/runtime/CSharp/Antlr4BuildTasks/Antlr4BuildTasks.csproj
index 84a93182..bbb06e42 100644
--- a/runtime/CSharp/Antlr4BuildTasks/Antlr4BuildTasks.csproj
+++ b/runtime/CSharp/Antlr4BuildTasks/Antlr4BuildTasks.csproj
@@ -9,8 +9,8 @@
     <AssemblyName>Antlr4BuildTasks</AssemblyName>
 
     <AssemblyVersion>4.6.0.0</AssemblyVersion>
-    <FileVersion>4.6.6.0</FileVersion>
-    <InformationalVersion>4.6.6</InformationalVersion>
+    <FileVersion>4.6.7.0</FileVersion>
+    <InformationalVersion>4.6.7-dev</InformationalVersion>
     <Description>MSBuild tasks for ANTLR 4 code generation.</Description>
     <Copyright>Copyright © Sam Harwell 2015</Copyright>
     <Company>Tunnel Vision Laboratories, LLC</Company>
diff --git a/tool/pom.xml b/tool/pom.xml
index 44140015..d046aeac 100644
--- a/tool/pom.xml
+++ b/tool/pom.xml
@@ -10,7 +10,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.tunnelvisionlabs</groupId>
     <artifactId>antlr4-csharp</artifactId>
-    <version>4.6.6</version>
+    <version>4.6.7-SNAPSHOT</version>
     <packaging>jar</packaging>
 
     <name>ANTLR 4 Target C#</name>
@@ -68,7 +68,7 @@
         <url>https://github.com/tunnelvisionlabs/antlr4cs/tree/master</url>
         <connection>scm:git:git://github.com/tunnelvisionlabs/antlr4cs.git</connection>
         <developerConnection>scm:git:git@github.com:tunnelvisionlabs/antlr4cs.git</developerConnection>
-        <tag>v4.6.6</tag>
+        <tag>HEAD</tag>
     </scm>
 
     <dependencies>