diff --git a/src/controllers/api/inventoryController.ts b/src/controllers/api/inventoryController.ts
index e78bf3d8..4aa44387 100644
--- a/src/controllers/api/inventoryController.ts
+++ b/src/controllers/api/inventoryController.ts
@@ -78,19 +78,18 @@ const inventoryController: RequestHandler = async (request: Request, response: R
         }
     }
 
-    if (
-        typeof config.spoofMasteryRank === "number" &&
-        config.spoofMasteryRank >= 0 &&
-        config.spoofMasteryRank <= 5030
-    ) {
+    if (typeof config.spoofMasteryRank === "number" && config.spoofMasteryRank >= 0) {
         inventoryResponse.PlayerLevel = config.spoofMasteryRank;
-        inventoryResponse.XPInfo = [];
-        let numFrames = getExpRequiredForMr(config.spoofMasteryRank) / 6000;
-        while (numFrames-- > 0) {
-            inventoryResponse.XPInfo.push({
-                ItemType: "/Lotus/Powersuits/Mag/Mag",
-                XP: 1_600_000
-            });
+        if (!("xpBasedLevelCapDisabled" in request.query)) {
+            // This client has not been patched to accept any mastery rank, need to fake the XP.
+            inventoryResponse.XPInfo = [];
+            let numFrames = getExpRequiredForMr(Math.min(config.spoofMasteryRank, 5030)) / 6000;
+            while (numFrames-- > 0) {
+                inventoryResponse.XPInfo.push({
+                    ItemType: "/Lotus/Powersuits/Mag/Mag",
+                    XP: 1_600_000
+                });
+            }
         }
     }
 
diff --git a/static/webui/script.js b/static/webui/script.js
index 15db05d7..0475a730 100644
--- a/static/webui/script.js
+++ b/static/webui/script.js
@@ -123,7 +123,7 @@ window.itemListPromise = new Promise(resolve => {
 });
 
 function updateInventory() {
-    const req = $.get("/api/inventory.php?" + window.authz);
+    const req = $.get("/api/inventory.php?" + window.authz + "&xpBasedLevelCapDisabled=1");
     req.done(data => {
         window.itemListPromise.then(itemMap => {
             document.getElementById("warframe-list").innerHTML = "";
@@ -539,7 +539,7 @@ function doAcquireRiven() {
             })
         }).done(function () {
             // Get riven's assigned id
-            $.get("/api/inventory.php?" + window.authz).done(data => {
+            $.get("/api/inventory.php?" + window.authz + "&xpBasedLevelCapDisabled=1").done(data => {
                 for (const rawUpgrade of data.RawUpgrades) {
                     if (rawUpgrade.ItemType === uniqueName) {
                         // Add fingerprint to riven