diff --git a/v5/types.go b/v5/types.go
index 75437aa..7c195c7 100644
--- a/v5/types.go
+++ b/v5/types.go
@@ -939,13 +939,6 @@ type Element struct {
 	Ordering int    `json:"ordering,omitempty"`
 }
 
-// ActivityCallback activation callback
-type ActivityCallback struct {
-	ClientId  string   `json:"clientId"`
-	Activity  Activity `json:"activity"`
-	SystemUrl string   `json:"systemUrl,omitempty"`
-}
-
 // Activity struct
 type Activity struct {
 	Active bool `json:"active"`