diff --git a/build_files/build_environment/cmake/download.cmake b/build_files/build_environment/cmake/download.cmake
index 9e085eb012d..c05b2877f2d 100644
--- a/build_files/build_environment/cmake/download.cmake
+++ b/build_files/build_environment/cmake/download.cmake
@@ -100,3 +100,6 @@ download_source(HARU)
 download_source(ZSTD)
 download_source(FLEX)
 download_source(BROTLI)
+download_source(FMT)
+download_source(ROBINMAP)
+download_source(PYSTRING)
diff --git a/build_files/build_environment/cmake/versions.cmake b/build_files/build_environment/cmake/versions.cmake
index 28a27023818..a13d0695151 100644
--- a/build_files/build_environment/cmake/versions.cmake
+++ b/build_files/build_environment/cmake/versions.cmake
@@ -177,6 +177,23 @@ set(OPENIMAGEIO_HASH 3db5c5f0b3dc91597c75e5df09eb9072)
 set(OPENIMAGEIO_HASH_TYPE MD5)
 set(OPENIMAGEIO_FILE OpenImageIO-${OPENIMAGEIO_VERSION}.tar.gz)

+# 7.1.3 is currently oiio's preferred vesion although never versions may be available.
+# the preferred version can be found in oiio's externalpackages.cmake
+set(FMT_VERSION 7.1.3)
+set(FMT_URI https://github.com/fmtlib/fmt/archive/refs/tags/${FMT_VERSION}.tar.gz)
+set(FMT_HASH 5cae7072042b3043e12d53d50ef404bbb76949dad1de368d7f993a15c8c05ecc)
+set(FMT_HASH_TYPE SHA256)
+set(FMT_FILE fmt-${FMT_VERSION}.tar.gz)
+
+# 0.6.2 is currently oiio's preferred vesion although never versions may be available.
+# the preferred version can be found in oiio's externalpackages.cmake
+set(ROBINMAP_VERSION 0.6.2)
+set(ROBINMAP_URI https://github.com/Tessil/robin-map/archive/refs/tags/${ROBINMAP_VERSION}.tar.gz)
+set(ROBINMAP_HASH c08ec4b1bf1c85eb0d6432244a6a89862229da1cb834f3f90fba8dc35d8c8ef1)
+set(ROBINMAP_HASH_TYPE SHA256)
+set(ROBINMAP_FILE robin-map-${ROBINMAP_VERSION}.tar.gz)
+
+
 set(TIFF_VERSION 4.1.0)
 set(TIFF_URI http://download.osgeo.org/libtiff/tiff-${TIFF_VERSION}.tar.gz)
 set(TIFF_HASH 2165e7aba557463acc0664e71a3ed424)
@@ -354,6 +371,12 @@ set(YAMLCPP_HASH b45bf1089a382e81f6b661062c10d0c2)
 set(YAMLCPP_HASH_TYPE MD5)
 set(YAMLCPP_FILE yaml-cpp-${YAMLCPP_VERSION}.tar.gz)

+set(PYSTRING_VERSION 1.1.3)
+set(PYSTRING_URI https://codeload.github.com/imageworks/pystring/tar.gz/refs/tags/${PYSTRING_VERSION})
+set(PYSTRING_HASH f2c68786b359f5e4e62bed53bc4fb86d)
+set(PYSTRING_HASH_TYPE MD5)