diff --git a/aleksis/core/mixins.py b/aleksis/core/mixins.py
index d2a8c08dabe8b961a27b669dc387d83827243d00..a9500a5d206e56db7ce231fb2d0b2101f19f461c 100644
--- a/aleksis/core/mixins.py
+++ b/aleksis/core/mixins.py
@@ -121,7 +121,7 @@ class ExtensibleModel(models.Model, metaclass=_ExtensibleModelBase):
                 prev_version = versions[i-1]
 
                 for k, val in version.field_dict.items():
-                    prev_val = prev_version.get(k, None)
+                    prev_val = prev_version.field_dict.get(k, None)
                     if prev_val != val:
                         diff[k] = (prev_val, val)