diff --git a/docs/ref-supported.md b/docs/ref-supported.md
index 49aef86cd..6e5ebb20a 100644
--- a/docs/ref-supported.md
+++ b/docs/ref-supported.md
@@ -29,6 +29,7 @@ DOMA | Domain | Yes
 DSYS | Chapter of a Book Structure | Yes
 DTEL | Data Element | Yes
 ECAT | eCATT Test Script | Yes
+ECSD | eCATT System Data Container | Yes
 ECTC | eCATT Test Configuration | Yes
 ECTD | eCATT Test Data Container | Yes
 ECVO | eCATT Validation Object | Yes