/enums/ad_group_primary_status_reason.proto

--- v16/enums/ad_group_primary_status_reason.proto  2024-04-18 17:10:04.000000000 +0000
+++ v16-1/enums/ad_group_primary_status_reason.proto    2024-04-18 17:10:13.000000000 +0000
@@ -98,5 +98,9 @@
     // The AdGroup belongs to a Draft campaign. Contributes to
     // AdGroupPrimaryStatus.NOT_ELIGIBLE.
     CAMPAIGN_DRAFT = 16;
+
+    // Ad group has been paused due to prolonged low activity in serving.
+    // Contributes to AdGroupPrimaryStatus.PAUSED.
+    AD_GROUP_PAUSED_DUE_TO_LOW_ACTIVITY = 19;
   }
 }