diff --git a/.github/depends/zlib.sh b/.github/depends/zlib.sh
index fce05159c..3c2c8b259 100755
--- a/.github/depends/zlib.sh
+++ b/.github/depends/zlib.sh
@@ -27,9 +27,9 @@ while getopts "b:t:p:" c; do
 done
 
 mkdir $prefix || exit 1
-wget https://zlib.net/zlib-1.2.13.tar.gz || exit 1
-tar -xf zlib-1.2.13.tar.gz || exit 1
-cd zlib-1.2.13
+wget https://zlib.net/zlib-1.3.tar.gz || exit 1
+tar -xf zlib-1.3.tar.gz || exit 1
+cd zlib-1.3
 
 build()
 {
diff --git a/appveyor.yml b/appveyor.yml
index 3681b3b33..6f5034b8c 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -23,10 +23,10 @@ environment:
       boost_subdir: lib32-msvc-14.0
 build_script:
   - ps: |
-      appveyor DownloadFile http://zlib.net/zlib-1.2.13.tar.gz -FileName zlib-1.2.13.tar.gz
-      7z x zlib-1.2.13.tar.gz 2> $null
-      7z x zlib-1.2.13.tar 2> $null
-      cd zlib-1.2.13
+      appveyor DownloadFile http://zlib.net/zlib-1.3.tar.gz -FileName zlib-1.3.tar.gz
+      7z x zlib-1.3.tar.gz 2> $null
+      7z x zlib-1.3.tar 2> $null
+      cd zlib-1.3
 
       md build
       md prefix
@@ -34,7 +34,7 @@ build_script:
 
       cmake `
           -G $env:msvc `
-          -D CMAKE_INSTALL_PREFIX="$env:APPVEYOR_BUILD_FOLDER\zlib-1.2.13\prefix" `
+          -D CMAKE_INSTALL_PREFIX="$env:APPVEYOR_BUILD_FOLDER\zlib-1.3\prefix" `
           ..
       if ($LastExitCode -ne 0) { exit $LastExitCode }
 
@@ -52,7 +52,7 @@ build_script:
           -D MSGPACK_BUILD_EXAMPLES=ON `
           -D MSGPACK_BUILD_TESTS=ON `
           -D CMAKE_EXE_LINKER_FLAGS=/LIBPATH:"$env:boost_prefix\$env:boost_subdir" `
-          -D CMAKE_PREFIX_PATH="$env:boost_prefix;$env:APPVEYOR_BUILD_FOLDER\zlib-1.2.13\prefix" `
+          -D CMAKE_PREFIX_PATH="$env:boost_prefix;$env:APPVEYOR_BUILD_FOLDER\zlib-1.3\prefix" `
           -D CMAKE_INSTALL_PREFIX="$env:APPVEYOR_BUILD_FOLDER\prefix" `
           -D CMAKE_CXX_FLAGS="/D_VARIADIC_MAX=10 /EHsc /DBOOST_ALL_DYN_LINK" `
           ..
@@ -62,5 +62,5 @@ build_script:
       if ($LastExitCode -ne 0) { exit $LastExitCode }
 
 test_script:
-- set PATH=%PATH%;%APPVEYOR_BUILD_FOLDER%\zlib-1.2.13\build\Release;%APPVEYOR_BUILD_FOLDER%\build\release;%boost_prefix%\%boost_subdir%
+- set PATH=%PATH%;%APPVEYOR_BUILD_FOLDER%\zlib-1.3\build\Release;%APPVEYOR_BUILD_FOLDER%\build\release;%boost_prefix%\%boost_subdir%
 - ctest -VV -C Release