diff --git a/README.md b/README.md
index 13754f9..be31242 100644
--- a/README.md
+++ b/README.md
@@ -110,6 +110,7 @@ S3Proxy has broad compatibility with the S3 API, however, it does not support:
 * object tagging
 * object versioning, see [#74](https://github.com/andrewgaul/s3proxy/issues/74)
 * requester pays buckets
+* storage classes, e.g., REDUCED_REDUNDANCY, STANDARD_IA
 
 S3Proxy emulates the following operations: