diff --git a/avatica-server/pom.xml b/avatica-server/pom.xml
index 14f8d9d26e7..efaa4eb6e85 100644
--- a/avatica-server/pom.xml
+++ b/avatica-server/pom.xml
@@ -20,12 +20,12 @@ limitations under the License.
   <parent>
     <groupId>org.apache.calcite</groupId>
     <artifactId>calcite</artifactId>
-    <version>1.4.0-incubating</version>
+    <version>1.5.0-incubating-SNAPSHOT</version>
   </parent>
 
   <artifactId>calcite-avatica-server</artifactId>
   <packaging>jar</packaging>
-  <version>1.4.0-incubating</version>
+  <version>1.5.0-incubating-SNAPSHOT</version>
   <name>Calcite Avatica Server</name>
   <description>JDBC server.</description>
 
diff --git a/avatica/pom.xml b/avatica/pom.xml
index 16b854643d2..65e838ae7c7 100644
--- a/avatica/pom.xml
+++ b/avatica/pom.xml
@@ -20,12 +20,12 @@ limitations under the License.
   <parent>
     <groupId>org.apache.calcite</groupId>
     <artifactId>calcite</artifactId>
-    <version>1.4.0-incubating</version>
+    <version>1.5.0-incubating-SNAPSHOT</version>
   </parent>
 
   <artifactId>calcite-avatica</artifactId>
   <packaging>jar</packaging>
-  <version>1.4.0-incubating</version>
+  <version>1.5.0-incubating-SNAPSHOT</version>
   <name>Calcite Avatica</name>
   <description>JDBC driver framework.</description>
 
diff --git a/core/pom.xml b/core/pom.xml
index 1362652bc14..b05871f6cc3 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -20,12 +20,12 @@ limitations under the License.
   <parent>
     <groupId>org.apache.calcite</groupId>
     <artifactId>calcite</artifactId>
-    <version>1.4.0-incubating</version>
+    <version>1.5.0-incubating-SNAPSHOT</version>
   </parent>
 
   <artifactId>calcite-core</artifactId>
   <packaging>jar</packaging>
-  <version>1.4.0-incubating</version>
+  <version>1.5.0-incubating-SNAPSHOT</version>
   <name>Calcite Core</name>
   <description>Core Calcite APIs and engine.</description>
 
diff --git a/example/csv/pom.xml b/example/csv/pom.xml
index 86fa41fcc6b..3cf8c3743eb 100644
--- a/example/csv/pom.xml
+++ b/example/csv/pom.xml
@@ -20,12 +20,12 @@ limitations under the License.
   <parent>
     <groupId>org.apache.calcite</groupId>
     <artifactId>calcite-example</artifactId>
-    <version>1.4.0-incubating</version>
+    <version>1.5.0-incubating-SNAPSHOT</version>
   </parent>
 
   <artifactId>calcite-example-csv</artifactId>
   <packaging>jar</packaging>
-  <version>1.4.0-incubating</version>
+  <version>1.5.0-incubating-SNAPSHOT</version>
   <name>Calcite Example CSV</name>
   <description>An example Calcite provider that reads CSV files</description>
 
diff --git a/example/pom.xml b/example/pom.xml
index 6c05e607fe9..b8748e4753a 100644
--- a/example/pom.xml
+++ b/example/pom.xml
@@ -20,13 +20,13 @@ limitations under the License.
   <parent>
     <groupId>org.apache.calcite</groupId>
     <artifactId>calcite</artifactId>
-    <version>1.4.0-incubating</version>
+    <version>1.5.0-incubating-SNAPSHOT</version>
   </parent>
 
   <!-- The basics. -->
   <artifactId>calcite-example</artifactId>
   <packaging>pom</packaging>
-  <version>1.4.0-incubating</version>
+  <version>1.5.0-incubating-SNAPSHOT</version>
   <name>Calcite Examples</name>
   <description>Calcite examples</description>
 
diff --git a/linq4j/pom.xml b/linq4j/pom.xml
index 64f0bd039b5..215edb13a09 100644
--- a/linq4j/pom.xml
+++ b/linq4j/pom.xml
@@ -20,12 +20,12 @@ limitations under the License.
   <parent>
     <groupId>org.apache.calcite</groupId>
     <artifactId>calcite</artifactId>
-    <version>1.4.0-incubating</version>
+    <version>1.5.0-incubating-SNAPSHOT</version>
   </parent>
 
   <artifactId>calcite-linq4j</artifactId>
   <packaging>jar</packaging>
-  <version>1.4.0-incubating</version>
+  <version>1.5.0-incubating-SNAPSHOT</version>
   <name>Calcite Linq4j</name>
   <description>Calcite APIs for LINQ (Language-Integrated Query) in Java</description>
 
diff --git a/mongodb/pom.xml b/mongodb/pom.xml
index da4a93bf1db..fa00e110ecd 100644
--- a/mongodb/pom.xml
+++ b/mongodb/pom.xml
@@ -20,12 +20,12 @@ limitations under the License.
   <parent>
     <groupId>org.apache.calcite</groupId>
     <artifactId>calcite</artifactId>
-    <version>1.4.0-incubating</version>
+    <version>1.5.0-incubating-SNAPSHOT</version>
   </parent>
 
   <artifactId>calcite-mongodb</artifactId>
   <packaging>jar</packaging>
-  <version>1.4.0-incubating</version>
+  <version>1.5.0-incubating-SNAPSHOT</version>
   <name>Calcite MongoDB</name>
   <description>MongoDB adapter for Calcite</description>
 
diff --git a/plus/pom.xml b/plus/pom.xml
index f918e8fcea3..96ce755dea5 100644
--- a/plus/pom.xml
+++ b/plus/pom.xml
@@ -20,12 +20,12 @@ limitations under the License.
   <parent>
     <groupId>org.apache.calcite</groupId>
     <artifactId>calcite</artifactId>
-    <version>1.4.0-incubating</version>
+    <version>1.5.0-incubating-SNAPSHOT</version>
   </parent>
 
   <artifactId>calcite-plus</artifactId>
   <packaging>jar</packaging>
-  <version>1.4.0-incubating</version>
+  <version>1.5.0-incubating-SNAPSHOT</version>
   <name>Calcite Plus</name>
   <description>Miscellaneous extras for Calcite</description>
 
diff --git a/pom.xml b/pom.xml
index 9d51284fa71..b5defb3a0b7 100644
--- a/pom.xml
+++ b/pom.xml
@@ -27,7 +27,7 @@ limitations under the License.
   <groupId>org.apache.calcite</groupId>
   <artifactId>calcite</artifactId>
   <packaging>pom</packaging>
-  <version>1.4.0-incubating</version>
+  <version>1.5.0-incubating-SNAPSHOT</version>
 
   <!-- More project information. -->
   <name>Calcite</name>
@@ -61,7 +61,7 @@ limitations under the License.
     <connection>scm:git:https://git-wip-us.apache.org/repos/asf/incubator-calcite.git</connection>
     <developerConnection>scm:git:https://git-wip-us.apache.org/repos/asf/incubator-calcite.git</developerConnection>
     <url>https://github.com/apache/incubator-calcite</url>
-    <tag>calcite-1.4.0-incubating</tag>
+    <tag>HEAD</tag>
   </scm>
 
   <modules>
@@ -88,34 +88,34 @@ limitations under the License.
       <dependency>
         <groupId>org.apache.calcite</groupId>
         <artifactId>calcite-avatica</artifactId>
-        <version>1.4.0-incubating</version>
+        <version>1.5.0-incubating-SNAPSHOT</version>
       </dependency>
       <dependency>
         <groupId>org.apache.calcite</groupId>
         <artifactId>calcite-avatica</artifactId>
-        <version>1.4.0-incubating</version>
+        <version>1.5.0-incubating-SNAPSHOT</version>
         <type>test-jar</type>
       </dependency>
       <dependency>
         <groupId>org.apache.calcite</groupId>
         <artifactId>calcite-avatica-server</artifactId>
-        <version>1.4.0-incubating</version>
+        <version>1.5.0-incubating-SNAPSHOT</version>
       </dependency>
       <dependency>
         <groupId>org.apache.calcite</groupId>
         <artifactId>calcite-core</artifactId>
-        <version>1.4.0-incubating</version>
+        <version>1.5.0-incubating-SNAPSHOT</version>
       </dependency>
       <dependency>
         <groupId>org.apache.calcite</groupId>
         <artifactId>calcite-core</artifactId>
         <type>test-jar</type>
-        <version>1.4.0-incubating</version>
+        <version>1.5.0-incubating-SNAPSHOT</version>
       </dependency>
       <dependency>
         <groupId>org.apache.calcite</groupId>
         <artifactId>calcite-linq4j</artifactId>
-        <version>1.4.0-incubating</version>
+        <version>1.5.0-incubating-SNAPSHOT</version>
       </dependency>
 
       <!-- Now third-party dependencies, sorted by groupId and artifactId. -->
diff --git a/spark/pom.xml b/spark/pom.xml
index e0b4281cff2..d14f746e456 100644
--- a/spark/pom.xml
+++ b/spark/pom.xml
@@ -20,12 +20,12 @@ limitations under the License.
   <parent>
     <groupId>org.apache.calcite</groupId>
     <artifactId>calcite</artifactId>
-    <version>1.4.0-incubating</version>
+    <version>1.5.0-incubating-SNAPSHOT</version>
   </parent>
 
   <artifactId>calcite-spark</artifactId>
   <packaging>jar</packaging>
-  <version>1.4.0-incubating</version>
+  <version>1.5.0-incubating-SNAPSHOT</version>
   <name>Calcite Spark</name>
 
   <properties>
diff --git a/splunk/pom.xml b/splunk/pom.xml
index e5f5cc2e710..611971dcd3d 100644
--- a/splunk/pom.xml
+++ b/splunk/pom.xml
@@ -20,12 +20,12 @@ limitations under the License.
   <parent>
     <groupId>org.apache.calcite</groupId>
     <artifactId>calcite</artifactId>
-    <version>1.4.0-incubating</version>
+    <version>1.5.0-incubating-SNAPSHOT</version>
   </parent>
 
   <artifactId>calcite-splunk</artifactId>
   <packaging>jar</packaging>
-  <version>1.4.0-incubating</version>
+  <version>1.5.0-incubating-SNAPSHOT</version>
   <name>Calcite Splunk</name>
   <description>Splunk adapter for Calcite; also a JDBC driver for Splunk</description>
 
diff --git a/ubenchmark/pom.xml b/ubenchmark/pom.xml
index 62788129cab..15a7e6a99c8 100644
--- a/ubenchmark/pom.xml
+++ b/ubenchmark/pom.xml
@@ -20,7 +20,7 @@ limitations under the License.
   <parent>
     <groupId>org.apache.calcite</groupId>
     <artifactId>calcite</artifactId>
-    <version>1.4.0-incubating</version>
+    <version>1.5.0-incubating-SNAPSHOT</version>
   </parent>
 
   <properties>