diff --git a/README.md b/README.md
index 61565c0..d24cdfb 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,8 @@ The synthesis in only performed if the query came in via IPv6.
 
 ## TODO
 
+Not all features required by DNS64 are implemented, only basic AAAA synthesis.
+
 * [ ] Resolve PTR records
 * [ ] Follow CNAME records
 * [ ] Make resolver DNSSEC aware