diff --git a/README.md b/README.md
index cd5d2fc..c751fa9 100644
--- a/README.md
+++ b/README.md
@@ -101,12 +101,14 @@ Bugs, issues and contributions can be requested to both the mailing list or the
 ## Requirements & dependencies
 
 * Python v2.7+
-* Python v3.4+ ***[STALLED] (experimental: [see known issues](https://github.com/OfflineIMAP/offlineimap/issues?q=is%3Aissue+is%3Aopen+label%3APy3))***
 * six (required)
+* rfc6555 (required)
 * imaplib2 >= 2.57 (optional)
 * gssapi (optional), for Kerberos authentication
 * portalocker (optional), if you need to run offlineimap in Cygwin for Windows
 
+* Python v3.4+ ***[STALLED] (experimental: [see known issues](https://github.com/OfflineIMAP/offlineimap/issues?q=is%3Aissue+is%3Aopen+label%3APy3))***
+
 ## Documentation
 
 All current and updated documentation is on the [community's website][website].