diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index 39d868b8c..025819ba2 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -7,6 +7,9 @@ This file contains a high-level description of this package's evolution. Release
 
 ## 4.5.0 - TBD
 
+### 4.5.0-rc3 - September 27, 2017
+
+* [Update] Due to ongoing issues, native CDF5 support has been disabled by **default**.  You can use the options mentioned below (`--enable-cdf5` or `-DENABLE_CDF5=TRUE` for `configure` or `cmake`, respectively).  Just be aware that for the time being, Reading/Writing CDF5 files on 32-bit platforms may result in unexpected behavior when using extremely large variables.  For 32-bit platforms it is best to continue using `NC_FORMAT_64BIT_OFFSET`.
 * [Bug] Corrected an issue where older versions of curl might fail. See [GitHub #487](https://github.com/Unidata/netcdf-c/issues/487) for more information.
 * [Enhancement] Added options to enable/disable `CDF5` support at configure time for autotools and cmake-based builds.  The options are `--enable/disable-cdf5` and `ENABLE_CDF5`, respectively.  See [Github #484](https://github.com/Unidata/netcdf-c/issues/484) for more information.
 * [Bug Fix] Corrected an issue when subsetting a netcdf3 file via `nccopy -v/-V`. See [Github #425](https://github.com/Unidata/netcdf-c/issues/425) and [Github #463](https://github.com/Unidata/netcdf-c/issues/463) for more information.