diff --git a/.circleci/config.yml b/.circleci/config.yml
index 1241072..2fcac76 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -7,7 +7,7 @@ branches:
 jobs:
   build:
     docker:
-      - image: circleci/openjdk:8-jdk
+      - image: circleci/openjdk:11-jdk
 
     working_directory: ~/repo
 
diff --git a/doc/quickstart.rst b/doc/quickstart.rst
index b6fc42c..5f4127b 100644
--- a/doc/quickstart.rst
+++ b/doc/quickstart.rst
@@ -41,7 +41,7 @@ Now run |Rings|\ *.repl*:
 
 	$ rings.repl
 	Loading...
-	Rings 2.5.2: efficient Java/Scala library for polynomial rings
+	Rings 2.5.6: efficient Java/Scala library for polynomial rings
 
 	@ implicit val ring = MultivariateRing(Z, Array("x", "y", "z"))
 	ring: MultivariateRing[IntZ] = MultivariateRing(Z, Array("x", "y", "z"), LEX)
@@ -64,7 +64,7 @@ Java/Scala library
 
 .. code-block:: scala
 
-	libraryDependencies += "cc.redberry" %% "rings.scaladsl" % "2.5.2"
+	libraryDependencies += "cc.redberry" %% "rings.scaladsl" % "2.5.6"
 
 For using |Rings| solely in Java there is Maven artifact:
 
@@ -73,7 +73,7 @@ For using |Rings| solely in Java there is Maven artifact:
 	<dependency>
 	    <groupId>cc.redberry</groupId>
 	    <artifactId>rings</artifactId>
-	    <version>2.5.2</version>
+	    <version>2.5.6</version>
 	</dependency>
 
 
@@ -1047,7 +1047,7 @@ Full benchmarks can be found at :ref:`ref-benchmarks` page. Benchmarks presented
  - `Mathematica <http://www.wolfram.com/mathematica>`_ (version 11.1.1.0)
  - `Singular <https://www.singular.uni-kl.de>`_ (version 4.1.0)
  - `NTL <http://www.shoup.net/ntl/>`_ (version 10.4.0)
- - `FLINT <http://www.flintlib.org>`_ (version 2.5.2_1)
+ - `FLINT <http://www.flintlib.org>`_ (version 2.5.6_1)
 
 
 .. figure:: _static/gcd_z_5vars_rings_vs_singular.png
diff --git a/rings.repl/rings.repl b/rings.repl/rings.repl
index dbbf1d8..2607a4a 100755
--- a/rings.repl/rings.repl
+++ b/rings.repl/rings.repl
@@ -51,7 +51,7 @@ case $os in
     ;;
 esac
 
-ringsVersion=2.5.5
+ringsVersion=2.5.6
 ammArgs=()
 javaArgs=()
 
diff --git a/rings.scaladsl/build.sbt b/rings.scaladsl/build.sbt
index e16da96..932b600 100644
--- a/rings.scaladsl/build.sbt
+++ b/rings.scaladsl/build.sbt
@@ -4,7 +4,7 @@ organization := "cc.redberry"
 
 name := "rings.scaladsl"
 
-version := "2.5.5"
+version := "2.5.6"
 
 scalaVersion := "2.12.3"
 
@@ -15,7 +15,7 @@ moduleName := name.value
 resolvers += Resolver.mavenLocal
 
 libraryDependencies ++= Seq(
-  "cc.redberry" % "rings" % "2.5.5",
+  "cc.redberry" % "rings" % "2.5.6",
   "junit" % "junit" % "4.12" % Test,
   "com.novocode" % "junit-interface" % "0.11" % Test exclude("junit", "junit-dep")
 )
diff --git a/rings/pom.xml b/rings/pom.xml
index d5d711c..7b0b10f 100644
--- a/rings/pom.xml
+++ b/rings/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>cc.redberry</groupId>
     <artifactId>rings</artifactId>
-    <version>2.5.5</version>
+    <version>2.5.6</version>
     <packaging>jar</packaging>
     <name>rings</name>
     <url>https://github.com/PoslavskySV/rings/</url>