diff --git a/ZEreshkigal-AllinOneMod/config/config.json b/ZEreshkigal-AllinOneMod/config/config.json
index 936aee2..68256c2 100644
--- a/ZEreshkigal-AllinOneMod/config/config.json
+++ b/ZEreshkigal-AllinOneMod/config/config.json
@@ -76,6 +76,7 @@
         },
         "MaxInsuranceStorageTime": false,
         "AllTraders4Stars": false,
+        "PreventFenceMastering": true,
         "Remove FIR condition on quests": false
     },
     "raids": {
diff --git a/ZEreshkigal-AllinOneMod/src/traders.js b/ZEreshkigal-AllinOneMod/src/traders.js
index ac2f275..5b50168 100644
--- a/ZEreshkigal-AllinOneMod/src/traders.js
+++ b/ZEreshkigal-AllinOneMod/src/traders.js
@@ -104,6 +104,11 @@ class TradersModifications {
         }
 
         function lvlUp(traderID, sessionID) {
+            if (config.traders.PreventFenceMastering === true) {
+                if (traderID === "579dc571d53a0658a154fbec") {
+                    continue;
+                }
+            }
             let pmcData = ProfileController.getPmcProfile(sessionID);
             let loyaltyLevels = DatabaseServer.tables.traders[traderID].base.loyalty.loyaltyLevels;