diff --git a/mitreattack/navlayers/core/layerobj.py b/mitreattack/navlayers/core/layerobj.py
index 97cf0e13..20c204c4 100644
--- a/mitreattack/navlayers/core/layerobj.py
+++ b/mitreattack/navlayers/core/layerobj.py
@@ -34,6 +34,7 @@ def __init__(self, name, domain):
         self.name = name
         self.__description = UNSETVALUE
         self.domain = domain
+        self.__customDataURL = UNSETVALUE
         self.__filters = UNSETVALUE
         self.__sorting = UNSETVALUE
         self.__layout = UNSETVALUE
@@ -107,6 +108,16 @@ def domain(self, domain):
             dom = dom.split("-")[-1] + "-attack"
         categoryChecker(type(self).__name__, dom, ["enterprise-attack", "mobile-attack", "ics-attack"], "domain")
         self.__domain = domain
+        
+    @property
+    def customDataURL(self):
+        if self.__customDataURL != UNSETVALUE:
+            return self.__customDataURL
+    
+    @customDataURL.setter
+    def customDataURL(self, customDataURL):
+        typeChecker(type(self).__name__, customDataURL, str, "customDataURL")
+        self.__customDataURL = customDataURL
 
     @property
     def description(self):
diff --git a/mitreattack/navlayers/core/versions.py b/mitreattack/navlayers/core/versions.py
index fa2342e5..6ef86047 100644
--- a/mitreattack/navlayers/core/versions.py
+++ b/mitreattack/navlayers/core/versions.py
@@ -60,12 +60,14 @@ def layer(self, layer):
         """Setter for layer."""
         typeChecker(type(self).__name__, layer, str, "layer")
         try:
-            categoryChecker(type(self).__name__, layer, ["3.0", "4.0", "4.1", "4.2", "4.3"], "layer version")
+            categoryChecker(type(self).__name__, layer, ["3.0", "4.0", "4.1", "4.2", "4.3", "4.4"], "layer version")
         except BadInput:
             print(
                 f"[WARNING] - unrecognized layer version {layer}. Defaulting to the 4.3 schema, this may result in "
                 f"unexpected behavior."
             )
+            layer = "4.3"
+            
         if layer in ["3.0", "4.0", "4.1", "4.2"]:
             print(f"[NOTICE] - Forcibly upgrading version from {layer} to 4.3.")
             layer = "4.3"