diff --git a/meshroom/core/attribute.py b/meshroom/core/attribute.py
index ac576404..be1aec82 100644
--- a/meshroom/core/attribute.py
+++ b/meshroom/core/attribute.py
@@ -330,10 +330,15 @@ class ListAttribute(Attribute):
             self.extend(newValue)
         self.requestGraphUpdate()
 
-    def upgradeValue(self, exportedValue):
-        values = exportedValue if isinstance(exportedValue, list) else [exportedValue]
+    def upgradeValue(self, exportedValues):
+        if not isinstance(exportedValues, list):
+            if isinstance(exportedValues, ListAttribute) or Attribute.isLinkExpression(exportedValues):
+                self._set_value(exportedValues)
+                return
+            raise RuntimeError("ListAttribute.upgradeValue: the given value is of type " + str(type(exportedValues)) + " but a 'list' is expected.")
+
         attrs = []
-        for v in values:
+        for v in exportedValues:
             a = attributeFactory(self.attributeDesc.elementDesc, None, self.isOutput, self.node, self)
             a.upgradeValue(v)
             attrs.append(a)
diff --git a/meshroom/nodes/aliceVision/CameraInit.py b/meshroom/nodes/aliceVision/CameraInit.py
index ba46d8eb..9663bf1b 100644
--- a/meshroom/nodes/aliceVision/CameraInit.py
+++ b/meshroom/nodes/aliceVision/CameraInit.py
@@ -1,4 +1,4 @@
-__version__ = "5.0"
+__version__ = "6.0"
 
 import os
 import json
@@ -255,12 +255,22 @@ The metadata needed are:
     ]
 
     def upgradeAttributeValues(self, attrValues, fromVersion):
-        if fromVersion <= Version(4, 0):
+        # Starting with version 5, the focal length is now split on x and y
+        if fromVersion < Version(5, 0):
             for intrinsic in attrValues['intrinsics']:
-                # focal length is now split on x and y
                 pxFocalLength = intrinsic['pxFocalLength']
                 if not isinstance(pxFocalLength, dict):
                     intrinsic['pxFocalLength'] = {"x": pxFocalLength, "y": pxFocalLength}
+
+        # Starting with version 6, the principal point is now relative to the image center
+        if fromVersion < Version(6, 0):
+            for intrinsic in attrValues['intrinsics']:
+                principalPoint = intrinsic['principalPoint']
+                intrinsic['principalPoint'] = {
+                    "x": int(principalPoint["x"] - 0.5 * intrinsic['width']),
+                    "y": int(principalPoint["y"] - 0.5 * intrinsic['height'])
+                    }
+
         return attrValues
 
     def readSfMData(self, sfmFile):
@@ -328,7 +338,7 @@ The metadata needed are:
                     view['metadata'] = json.loads(view['metadata'])
 
             sfmData = {
-                "version": [1, 2, 0],
+                "version": [1, 2, 1],
                 "views": views + newViews,
                 "intrinsics": intrinsics,
                 "featureFolder": "",