diff --git a/Dockerfile b/Dockerfile
index c035616c64789b1dac1333d39e16d867a876c0ce..fa0fb6838cc4e4d6e433cf7f33882c9d67c65340 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -7,7 +7,7 @@ ENV BUILD /build
 ENV OPT /opt
 
 # last checked for updates Nov 14 2016
-ENV ZLIB_VERSION 1.2.8
+ENV ZLIB_VERSION 1.2.11
 ENV JPEG_VERSION 6b
 ENV SZIP_VERSION 2.1
 ENV HDF4_VERSION 4.2.12