diff --git a/Dockerfile b/Dockerfile
index 99d2f681c351fe9e7da640a1f466d1e8b2f06317..9c239435ee7608d0dba039551b5fec7c44b07242 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