diff --git a/Dockerfile b/Dockerfile
index 26f844b..f3625f9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,7 @@
 FROM openjdk:8-jre-alpine
 ENV AOZORA_EPUB3 AozoraEpub3-1.1.0b46.zip
 ENV KINDLEGEN kindlegen_linux_2.6_i386_v2_9.tar.gz
-ENV NAROU_VERSION 3.1.9
+ENV NAROU_VERSION 3.1.11
 WORKDIR /opt/narou
 
 RUN apk --update add ruby ruby-io-console ruby-json wget unzip && rm -rf /var/cache/apk/*
diff --git a/Makefile b/Makefile
index 57efac6..9e7c01f 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 
-RELEASE_VERSION = v1.5
+RELEASE_VERSION = v1.6
 VERSION = latest
 
 OPTIONS = \