diff --git a/specs/core/1_custody-game.md b/specs/core/1_custody-game.md
index 0e3138a29..d6c79c96d 100644
--- a/specs/core/1_custody-game.md
+++ b/specs/core/1_custody-game.md
@@ -131,7 +131,7 @@ The following types are defined, mapping into `DomainType` (little endian):
 
 | Name | Value |
 | - | - |
-| `DOMAIN_CUSTODY_BIT_CHALLENGE` | `0x05000000` |
+| `DOMAIN_CUSTODY_BIT_CHALLENGE` | `0x06000000` |
 
 ### TODO PLACEHOLDER