diff --git a/README.md b/README.md
index 0a164e9..3235cc4 100644
--- a/README.md
+++ b/README.md
@@ -187,7 +187,7 @@ If you’re a Maven user, you can use the dependencies by adding the following t
         <dependency>
             <groupId>org.springframework.grpc</groupId>
             <artifactId>spring-grpc-dependencies</artifactId>
-            <version>0.3.0</version>
+            <version>0.4.0-SNAPSHOT</version>
             <type>pom</type>
             <scope>import</scope>
         </dependency>
@@ -201,7 +201,7 @@ As shown in the snippet below this can then be followed by version-less declarat
 
 ```gradle
 dependencies {
-  implementation platform("org.springframework.grpc:spring-grpc-dependencies:0.3.0")
+  implementation platform("org.springframework.grpc:spring-grpc-dependencies:0.4.0-SNAPSHOT")
 }
 ```
 
diff --git a/pom.xml b/pom.xml
index 8605fbc..89ffdef 100644
--- a/pom.xml
+++ b/pom.xml
@@ -5,7 +5,7 @@
 
 	<groupId>org.springframework.grpc</groupId>
 	<artifactId>spring-grpc</artifactId>
-	<version>0.3.0</version>
+	<version>0.4.0-SNAPSHOT</version>
 
 	<packaging>pom</packaging>
 	<url>https://github.com/spring-projects-experimental/spring-grpc</url>
diff --git a/samples/grpc-server-netty-shaded/build.gradle b/samples/grpc-server-netty-shaded/build.gradle
index 0aeec02..14d8200 100644
--- a/samples/grpc-server-netty-shaded/build.gradle
+++ b/samples/grpc-server-netty-shaded/build.gradle
@@ -7,7 +7,7 @@ plugins {
 }
 
 group = 'com.example'
-version = '0.3.0'
+version = '0.4.0-SNAPSHOT'
 
 java {
     toolchain {
@@ -24,7 +24,7 @@ repositories {
 
 dependencyManagement {
     imports {
-        mavenBom 'org.springframework.grpc:spring-grpc-dependencies:0.3.0'
+        mavenBom 'org.springframework.grpc:spring-grpc-dependencies:0.4.0-SNAPSHOT'
     }
 }
 
diff --git a/samples/grpc-server-netty-shaded/pom.xml b/samples/grpc-server-netty-shaded/pom.xml
index cd861c2..0c80ff0 100644
--- a/samples/grpc-server-netty-shaded/pom.xml
+++ b/samples/grpc-server-netty-shaded/pom.xml
@@ -11,7 +11,7 @@
 	</parent>
 	<groupId>com.example</groupId>
 	<artifactId>grpc-server-netty-shaded</artifactId>
-	<version>0.3.0</version>
+	<version>0.4.0-SNAPSHOT</version>
 	<name>Spring gRPC Server Sample Netty Shaded</name>
 	<description>Demo project for Spring Boot</description>
 	<properties>
@@ -25,7 +25,7 @@
 			<dependency>
 				<groupId>org.springframework.grpc</groupId>
 				<artifactId>spring-grpc-dependencies</artifactId>
-				<version>0.3.0</version>
+				<version>0.4.0-SNAPSHOT</version>
 				<type>pom</type>
 				<scope>import</scope>
 			</dependency>
diff --git a/samples/grpc-server/build.gradle b/samples/grpc-server/build.gradle
index a210a07..385541e 100644
--- a/samples/grpc-server/build.gradle
+++ b/samples/grpc-server/build.gradle
@@ -7,7 +7,7 @@ plugins {
 }
 
 group = 'com.example'
-version = '0.3.0'
+version = '0.4.0-SNAPSHOT'
 
 java {
     toolchain {
@@ -24,7 +24,7 @@ repositories {
 
 dependencyManagement {
     imports {
-        mavenBom 'org.springframework.grpc:spring-grpc-dependencies:0.3.0'
+        mavenBom 'org.springframework.grpc:spring-grpc-dependencies:0.4.0-SNAPSHOT'
     }
 }
 
diff --git a/samples/grpc-server/pom.xml b/samples/grpc-server/pom.xml
index b0f96f1..4b635c2 100644
--- a/samples/grpc-server/pom.xml
+++ b/samples/grpc-server/pom.xml
@@ -11,7 +11,7 @@
 	</parent>
 	<groupId>org.springframework.grpc</groupId>
 	<artifactId>grpc-server-sample</artifactId>
-	<version>0.3.0</version>
+	<version>0.4.0-SNAPSHOT</version>
 	<name>Spring gRPC Server Sample</name>
 	<description>Demo project for Spring gRPC</description>
 	<url />
@@ -38,7 +38,7 @@
 			<dependency>
 				<groupId>org.springframework.grpc</groupId>
 				<artifactId>spring-grpc-dependencies</artifactId>
-				<version>0.3.0</version>
+				<version>0.4.0-SNAPSHOT</version>
 				<type>pom</type>
 				<scope>import</scope>
 			</dependency>
diff --git a/samples/grpc-tomcat-secure/pom.xml b/samples/grpc-tomcat-secure/pom.xml
index 43ce757..4f3c73f 100644
--- a/samples/grpc-tomcat-secure/pom.xml
+++ b/samples/grpc-tomcat-secure/pom.xml
@@ -11,7 +11,7 @@
 	</parent>
 	<groupId>org.springframework.grpc</groupId>
 	<artifactId>grpc-tomcat-secure-sample</artifactId>
-	<version>0.3.0</version>
+	<version>0.4.0-SNAPSHOT</version>
 	<name>Spring gRPC Server Sample</name>
 	<description>Demo project for Spring gRPC</description>
 	<url />
@@ -38,7 +38,7 @@
 			<dependency>
 				<groupId>org.springframework.grpc</groupId>
 				<artifactId>spring-grpc-dependencies</artifactId>
-				<version>0.3.0</version>
+				<version>0.4.0-SNAPSHOT</version>
 				<type>pom</type>
 				<scope>import</scope>
 			</dependency>
diff --git a/samples/grpc-tomcat/pom.xml b/samples/grpc-tomcat/pom.xml
index 5c44c40..201548a 100644
--- a/samples/grpc-tomcat/pom.xml
+++ b/samples/grpc-tomcat/pom.xml
@@ -11,7 +11,7 @@
 	</parent>
 	<groupId>org.springframework.grpc</groupId>
 	<artifactId>grpc-tomcat-sample</artifactId>
-	<version>0.3.0</version>
+	<version>0.4.0-SNAPSHOT</version>
 	<name>Spring gRPC Server Sample</name>
 	<description>Demo project for Spring gRPC</description>
 	<url />
@@ -38,7 +38,7 @@
 			<dependency>
 				<groupId>org.springframework.grpc</groupId>
 				<artifactId>spring-grpc-dependencies</artifactId>
-				<version>0.3.0</version>
+				<version>0.4.0-SNAPSHOT</version>
 				<type>pom</type>
 				<scope>import</scope>
 			</dependency>
diff --git a/samples/grpc-webflux/build.gradle b/samples/grpc-webflux/build.gradle
index 306fe1b..b3e04c4 100644
--- a/samples/grpc-webflux/build.gradle
+++ b/samples/grpc-webflux/build.gradle
@@ -7,7 +7,7 @@ plugins {
 }
 
 group = 'com.example'
-version = '0.3.0'
+version = '0.4.0-SNAPSHOT'
 
 java {
     toolchain {
@@ -24,7 +24,7 @@ repositories {
 
 dependencyManagement {
     imports {
-        mavenBom 'org.springframework.grpc:spring-grpc-dependencies:0.3.0'
+        mavenBom 'org.springframework.grpc:spring-grpc-dependencies:0.4.0-SNAPSHOT'
     }
 }
 
diff --git a/samples/grpc-webflux/pom.xml b/samples/grpc-webflux/pom.xml
index 4081b9d..b4e0773 100644
--- a/samples/grpc-webflux/pom.xml
+++ b/samples/grpc-webflux/pom.xml
@@ -11,7 +11,7 @@
 	</parent>
 	<groupId>org.springframework.grpc</groupId>
 	<artifactId>grpc-webflux-sample</artifactId>
-	<version>0.3.0</version>
+	<version>0.4.0-SNAPSHOT</version>
 	<name>Spring gRPC Server Sample</name>
 	<description>Demo project for Spring gRPC</description>
 	<url />
@@ -38,7 +38,7 @@
 			<dependency>
 				<groupId>org.springframework.grpc</groupId>
 				<artifactId>spring-grpc-dependencies</artifactId>
-				<version>0.3.0</version>
+				<version>0.4.0-SNAPSHOT</version>
 				<type>pom</type>
 				<scope>import</scope>
 			</dependency>
diff --git a/samples/pom.xml b/samples/pom.xml
index b7201b2..6030afa 100644
--- a/samples/pom.xml
+++ b/samples/pom.xml
@@ -6,12 +6,12 @@
 	<parent>
 		<groupId>org.springframework.grpc</groupId>
 		<artifactId>spring-grpc</artifactId>
-		<version>0.3.0</version>
+		<version>0.4.0-SNAPSHOT</version>
 	</parent>
 
 	<groupId>org.springframework.grpc</groupId>
 	<artifactId>parent-samples</artifactId>
-	<version>0.3.0</version>
+	<version>0.4.0-SNAPSHOT</version>
 	<packaging>pom</packaging>
 	<name>Parent Demo</name>
 
diff --git a/spring-grpc-core/pom.xml b/spring-grpc-core/pom.xml
index 59a131a..065d761 100644
--- a/spring-grpc-core/pom.xml
+++ b/spring-grpc-core/pom.xml
@@ -6,7 +6,7 @@
 	<parent>
 		<groupId>org.springframework.grpc</groupId>
 		<artifactId>spring-grpc</artifactId>
-		<version>0.3.0</version>
+		<version>0.4.0-SNAPSHOT</version>
 	</parent>
 	<artifactId>spring-grpc-core</artifactId>
 	<packaging>jar</packaging>
diff --git a/spring-grpc-dependencies/pom.xml b/spring-grpc-dependencies/pom.xml
index 4ad0e2d..7f8f5d7 100644
--- a/spring-grpc-dependencies/pom.xml
+++ b/spring-grpc-dependencies/pom.xml
@@ -6,7 +6,7 @@
 
 	<groupId>org.springframework.grpc</groupId>
 	<artifactId>spring-grpc-dependencies</artifactId>
-	<version>0.3.0</version>
+	<version>0.4.0-SNAPSHOT</version>
 	<packaging>pom</packaging>
 
 	<name>Spring gRPC dependencies</name>
diff --git a/spring-grpc-docs/pom.xml b/spring-grpc-docs/pom.xml
index a6cdbfa..d28e940 100644
--- a/spring-grpc-docs/pom.xml
+++ b/spring-grpc-docs/pom.xml
@@ -6,7 +6,7 @@
 	<parent>
 		<groupId>org.springframework.grpc</groupId>
 		<artifactId>spring-grpc</artifactId>
-		<version>0.3.0</version>
+		<version>0.4.0-SNAPSHOT</version>
 	</parent>
 	<artifactId>spring-grpc-docs</artifactId>
 	<name>Spring gRPC Docs</name>
diff --git a/spring-grpc-docs/src/main/antora/modules/ROOT/pages/getting-started.adoc b/spring-grpc-docs/src/main/antora/modules/ROOT/pages/getting-started.adoc
index 2e2a4d8..a1c3ee0 100644
--- a/spring-grpc-docs/src/main/antora/modules/ROOT/pages/getting-started.adoc
+++ b/spring-grpc-docs/src/main/antora/modules/ROOT/pages/getting-started.adoc
@@ -193,7 +193,7 @@ If you’re a Maven user, you can use the dependencies by adding the following t
         <dependency>
             <groupId>org.springframework.grpc</groupId>
             <artifactId>spring-grpc-dependencies</artifactId>
-            <version>0.3.0</version>
+            <version>0.4.0-SNAPSHOT</version>
             <type>pom</type>
             <scope>import</scope>
         </dependency>
@@ -208,7 +208,7 @@ As shown in the snippet below this can then be followed by version-less declarat
 [source,gradle]
 ----
 dependencies {
-  implementation platform("org.springframework.grpc:spring-grpc-dependencies:0.3.0")
+  implementation platform("org.springframework.grpc:spring-grpc-dependencies:0.4.0-SNAPSHOT")
 }
 ----
 
diff --git a/spring-grpc-docs/src/main/antora/modules/ROOT/pages/whats-new.adoc b/spring-grpc-docs/src/main/antora/modules/ROOT/pages/whats-new.adoc
index 63f60ca..f595b5e 100644
--- a/spring-grpc-docs/src/main/antora/modules/ROOT/pages/whats-new.adoc
+++ b/spring-grpc-docs/src/main/antora/modules/ROOT/pages/whats-new.adoc
@@ -1,8 +1,24 @@
 = What's new?
 
+:page-section-summary-toc: 1
+
+[[what-s-new-in-0-4-0-since-0-3-0]]
+== What's New in 0.4.0 Since 0.3.0
+
+This section covers the changes made from version 0.2.0 to version 0.3.0.
+
+=== Channel Factory
+The `GrpcChannelFactory` has a new interface and its methods now return a `Channel` (instead of a `ChannelBuilder`).
+The `createChannel()` method is overloaded with a new method that accepts a `ChannelBuilderOptions` which can be used to configure the channel before it is created.
+
+=== Client Side Observability
+A gRPC client will generate a new span for each RPC call. The span will be automatically closed when the call is completed.
+
+=== Security in Servlet Containers
+Spring Security works with gRPC servers running in servlet containers. You can use all your favourite Spring Security features to secure your gRPC services.
+
 [[what-s-new-in-0-3-0-since-0-2-0]]
 == What's New in 0.3.0 Since 0.2.0
-:page-section-summary-toc: 1
 
 This section covers the changes made from version 0.2.0 to version 0.3.0.
 
diff --git a/spring-grpc-spring-boot-autoconfigure/pom.xml b/spring-grpc-spring-boot-autoconfigure/pom.xml
index bc6e5fe..5eeb96e 100644
--- a/spring-grpc-spring-boot-autoconfigure/pom.xml
+++ b/spring-grpc-spring-boot-autoconfigure/pom.xml
@@ -6,7 +6,7 @@
 	<parent>
 		<groupId>org.springframework.grpc</groupId>
 		<artifactId>spring-grpc</artifactId>
-		<version>0.3.0</version>
+		<version>0.4.0-SNAPSHOT</version>
 	</parent>
 	<artifactId>spring-grpc-spring-boot-autoconfigure</artifactId>
 	<packaging>jar</packaging>
diff --git a/spring-grpc-spring-boot-starter/pom.xml b/spring-grpc-spring-boot-starter/pom.xml
index 245ef55..42b5ff9 100644
--- a/spring-grpc-spring-boot-starter/pom.xml
+++ b/spring-grpc-spring-boot-starter/pom.xml
@@ -6,7 +6,7 @@
 	<parent>
 		<groupId>org.springframework.grpc</groupId>
 		<artifactId>spring-grpc</artifactId>
-		<version>0.3.0</version>
+		<version>0.4.0-SNAPSHOT</version>
 	</parent>
 	<artifactId>spring-grpc-spring-boot-starter</artifactId>
 	<packaging>jar</packaging>
diff --git a/spring-grpc-test/pom.xml b/spring-grpc-test/pom.xml
index fc12f2a..428523a 100644
--- a/spring-grpc-test/pom.xml
+++ b/spring-grpc-test/pom.xml
@@ -6,7 +6,7 @@
 	<parent>
 		<groupId>org.springframework.grpc</groupId>
 		<artifactId>spring-grpc</artifactId>
-		<version>0.3.0</version>
+		<version>0.4.0-SNAPSHOT</version>
 	</parent>
 	<artifactId>spring-grpc-test</artifactId>
 	<name>Spring gRPC Test</name>