diff --git a/README.md b/README.md
index f8cc3f3..682f08b 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,7 @@ Versions
 IK version | ES version
 -----------|-----------
 master | 5.x -> master
-5.6.5| 5.6.5
+5.6.6| 5.6.6
 5.6.4| 5.6.4
 5.5.3| 5.5.3
 5.4.3| 5.4.3
diff --git a/pom.xml b/pom.xml
index b682471..b7e5f3c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,7 +12,7 @@
     <inceptionYear>2011</inceptionYear>
 
     <properties>
-        <elasticsearch.version>5.6.5</elasticsearch.version>
+        <elasticsearch.version>5.6.6</elasticsearch.version>
         <maven.compiler.target>1.8</maven.compiler.target>
         <elasticsearch.assembly.descriptor>${project.basedir}/src/main/assemblies/plugin.xml</elasticsearch.assembly.descriptor>
         <elasticsearch.plugin.name>analysis-ik</elasticsearch.plugin.name>