diff --git a/2.1/Dockerfile b/2.1/Dockerfile
index 368722a1f..0e442589a 100644
--- a/2.1/Dockerfile
+++ b/2.1/Dockerfile
@@ -8,8 +8,8 @@ RUN mkdir -p /usr/local/etc \
 	} >> /usr/local/etc/gemrc
 
 ENV RUBY_MAJOR 2.1
-ENV RUBY_VERSION 2.1.8
-ENV RUBY_DOWNLOAD_SHA256 afd832b8d5ecb2e3e1477ec6a9408fdf9898ee73e4c5df17a2b2cb36bd1c355d
+ENV RUBY_VERSION 2.1.9
+ENV RUBY_DOWNLOAD_SHA256 034cb9c50676d2c09b3b6cf5c8003585acea05008d9a29fa737c54d52c1eb70c
 ENV RUBYGEMS_VERSION 2.6.2
 
 # some of ruby's build scripts are written in ruby
diff --git a/2.1/alpine/Dockerfile b/2.1/alpine/Dockerfile
index 0b0029b5c..623000c5f 100644
--- a/2.1/alpine/Dockerfile
+++ b/2.1/alpine/Dockerfile
@@ -8,8 +8,8 @@ RUN mkdir -p /usr/local/etc \
 	} >> /usr/local/etc/gemrc
 
 ENV RUBY_MAJOR 2.1
-ENV RUBY_VERSION 2.1.8
-ENV RUBY_DOWNLOAD_SHA256 afd832b8d5ecb2e3e1477ec6a9408fdf9898ee73e4c5df17a2b2cb36bd1c355d
+ENV RUBY_VERSION 2.1.9
+ENV RUBY_DOWNLOAD_SHA256 034cb9c50676d2c09b3b6cf5c8003585acea05008d9a29fa737c54d52c1eb70c
 ENV RUBYGEMS_VERSION 2.6.2
 
 # some of ruby's build scripts are written in ruby
diff --git a/2.1/slim/Dockerfile b/2.1/slim/Dockerfile
index e08c8fb17..d004bebb7 100644
--- a/2.1/slim/Dockerfile
+++ b/2.1/slim/Dockerfile
@@ -21,8 +21,8 @@ RUN mkdir -p /usr/local/etc \
 	} >> /usr/local/etc/gemrc
 
 ENV RUBY_MAJOR 2.1
-ENV RUBY_VERSION 2.1.8
-ENV RUBY_DOWNLOAD_SHA256 afd832b8d5ecb2e3e1477ec6a9408fdf9898ee73e4c5df17a2b2cb36bd1c355d
+ENV RUBY_VERSION 2.1.9
+ENV RUBY_DOWNLOAD_SHA256 034cb9c50676d2c09b3b6cf5c8003585acea05008d9a29fa737c54d52c1eb70c
 ENV RUBYGEMS_VERSION 2.6.2
 
 # some of ruby's build scripts are written in ruby