diff --git a/cmake/Python_version.in b/cmake/Python_version.in
index 67b48af46..ef2754d2d 100644
--- a/cmake/Python_version.in
+++ b/cmake/Python_version.in
@@ -1 +1 @@
-@xgboost_VERSION_MAJOR@.@xgboost_VERSION_MINOR@.@xgboost_VERSION_PATCH@-dev
\ No newline at end of file
+@xgboost_VERSION_MAJOR@.@xgboost_VERSION_MINOR@.@xgboost_VERSION_PATCH@rc1
\ No newline at end of file
diff --git a/jvm-packages/pom.xml b/jvm-packages/pom.xml
index cd5fedf7d..43d05847a 100644
--- a/jvm-packages/pom.xml
+++ b/jvm-packages/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>ml.dmlc</groupId>
     <artifactId>xgboost-jvm_2.12</artifactId>
-    <version>1.6.0-SNAPSHOT</version>
+    <version>1.6.0-RC1</version>
     <packaging>pom</packaging>
     <name>XGBoost JVM Package</name>
     <description>JVM Package for XGBoost</description>
diff --git a/jvm-packages/xgboost4j-example/pom.xml b/jvm-packages/xgboost4j-example/pom.xml
index da6ef2be6..977ad3a4c 100644
--- a/jvm-packages/xgboost4j-example/pom.xml
+++ b/jvm-packages/xgboost4j-example/pom.xml
@@ -6,10 +6,10 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.6.0-SNAPSHOT</version>
+        <version>1.6.0-RC1</version>
     </parent>
     <artifactId>xgboost4j-example_2.12</artifactId>
-    <version>1.6.0-SNAPSHOT</version>
+    <version>1.6.0-RC1</version>
     <packaging>jar</packaging>
     <build>
         <plugins>
@@ -26,7 +26,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j-spark_${scala.binary.version}</artifactId>
-            <version>1.6.0-SNAPSHOT</version>
+            <version>1.6.0-RC1</version>
         </dependency>
         <dependency>
             <groupId>org.apache.spark</groupId>
@@ -37,7 +37,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j-flink_${scala.binary.version}</artifactId>
-            <version>1.6.0-SNAPSHOT</version>
+            <version>1.6.0-RC1</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
diff --git a/jvm-packages/xgboost4j-flink/pom.xml b/jvm-packages/xgboost4j-flink/pom.xml
index f9bd4aa2a..47b868fe1 100644
--- a/jvm-packages/xgboost4j-flink/pom.xml
+++ b/jvm-packages/xgboost4j-flink/pom.xml
@@ -6,10 +6,10 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.6.0-SNAPSHOT</version>
+        <version>1.6.0-RC1</version>
     </parent>
     <artifactId>xgboost4j-flink_2.12</artifactId>
-    <version>1.6.0-SNAPSHOT</version>
+    <version>1.6.0-RC1</version>
     <build>
         <plugins>
             <plugin>
@@ -26,7 +26,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j_${scala.binary.version}</artifactId>
-            <version>1.6.0-SNAPSHOT</version>
+            <version>1.6.0-RC1</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
diff --git a/jvm-packages/xgboost4j-gpu/pom.xml b/jvm-packages/xgboost4j-gpu/pom.xml
index 2a2abaee8..19de82c1e 100644
--- a/jvm-packages/xgboost4j-gpu/pom.xml
+++ b/jvm-packages/xgboost4j-gpu/pom.xml
@@ -6,10 +6,10 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.6.0-SNAPSHOT</version>
+        <version>1.6.0-RC1</version>
     </parent>
     <artifactId>xgboost4j-gpu_2.12</artifactId>
-    <version>1.6.0-SNAPSHOT</version>
+    <version>1.6.0-RC1</version>
     <packaging>jar</packaging>
 
     <dependencies>
diff --git a/jvm-packages/xgboost4j-spark-gpu/pom.xml b/jvm-packages/xgboost4j-spark-gpu/pom.xml
index daa5907c6..dcdcdf806 100644
--- a/jvm-packages/xgboost4j-spark-gpu/pom.xml
+++ b/jvm-packages/xgboost4j-spark-gpu/pom.xml
@@ -6,7 +6,7 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.6.0-SNAPSHOT</version>
+        <version>1.6.0-RC1</version>
     </parent>
     <artifactId>xgboost4j-spark-gpu_2.12</artifactId>
     <build>
@@ -24,7 +24,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j-gpu_${scala.binary.version}</artifactId>
-            <version>1.6.0-SNAPSHOT</version>
+            <version>1.6.0-RC1</version>
         </dependency>
         <dependency>
             <groupId>org.apache.spark</groupId>
diff --git a/jvm-packages/xgboost4j-spark/pom.xml b/jvm-packages/xgboost4j-spark/pom.xml
index 3fe38f875..7ca00afb7 100644
--- a/jvm-packages/xgboost4j-spark/pom.xml
+++ b/jvm-packages/xgboost4j-spark/pom.xml
@@ -6,7 +6,7 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.6.0-SNAPSHOT</version>
+        <version>1.6.0-RC1</version>
     </parent>
     <artifactId>xgboost4j-spark_2.12</artifactId>
     <build>
@@ -24,7 +24,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j_${scala.binary.version}</artifactId>
-            <version>1.6.0-SNAPSHOT</version>
+            <version>1.6.0-RC1</version>
         </dependency>
         <dependency>
             <groupId>org.apache.spark</groupId>
diff --git a/jvm-packages/xgboost4j/pom.xml b/jvm-packages/xgboost4j/pom.xml
index d60a83b29..5f1f5a6ba 100644
--- a/jvm-packages/xgboost4j/pom.xml
+++ b/jvm-packages/xgboost4j/pom.xml
@@ -6,10 +6,10 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.6.0-SNAPSHOT</version>
+        <version>1.6.0-RC1</version>
     </parent>
     <artifactId>xgboost4j_2.12</artifactId>
-    <version>1.6.0-SNAPSHOT</version>
+    <version>1.6.0-RC1</version>
     <packaging>jar</packaging>
 
     <dependencies>
diff --git a/python-package/xgboost/VERSION b/python-package/xgboost/VERSION
index bcfbf475d..40ab7ec27 100644
--- a/python-package/xgboost/VERSION
+++ b/python-package/xgboost/VERSION
@@ -1 +1 @@
-1.6.0-dev
+1.6.0rc1