diff --git a/docker/dev/Dockerfile b/docker/dev/Dockerfile
index 2480e16..4479cce 100644
--- a/docker/dev/Dockerfile
+++ b/docker/dev/Dockerfile
@@ -8,7 +8,7 @@
 # RUN:
 #   docker run -e VMPOOLER_CONFIG -p 80:4567 -it vmpooler
 
-FROM jruby:9.2-jdk
+FROM jruby:9.3.1.0-jdk
 
 ENV RACK_ENV=production
 
diff --git a/docker/dev/Dockerfile-aio b/docker/dev/Dockerfile-aio
index 48a62d6..8bdb610 100644
--- a/docker/dev/Dockerfile-aio
+++ b/docker/dev/Dockerfile-aio
@@ -8,7 +8,7 @@
 # RUN:
 #   docker run -e VMPOOLER_CONFIG -p 80:4567 -it vmpooler
 
-FROM jruby:9.2.9-jdk
+FROM jruby:9.3.1.0-jdk
 
 RUN mkdir -p /var/lib/vmpooler