              model_state = self.to_state.models[app_label, model_name]
              # Are there any relationships out from this model? if so, punt it to the next phase.
              related_fields = []
              for field in new_app_cache.get_model(app_label, model_name)._meta.fields:
                  if hasattr(field, "rel"):
                      if hasattr(field.rel, "to"):
                          related_fields.append((field.name, field.rel.to._meta.app_label.lower(), field.rel.to._meta.object_name.lower()))
                      if hasattr(field.rel, "through") and not field.rel.though._meta.auto_created:
                          related_fields.append((field.name, field.rel.through._meta.app_label.lower(), field.rel.through._meta.object_name.lower()))
              if related_fields:
                  pending_add[app_label, model_name] = related_fields
 
</s> remove         if getattr(old_field, "rel"):
 </s> add         if old_field.rel: </s> remove         if getattr(new_field, "rel"):
 </s> add         if new_field.rel:
                if field.rel:
                    if field.rel.to:
              model_state = self.to_state.models[app_label, model_name]
              # Are there any relationships out from this model? if so, punt it to the next phase.
              related_fields = []
              for field in new_app_cache.get_model(app_label, model_name)._meta.fields:
                if field.rel:
                    if field.rel.to:
                if field.rel:
                    if field.rel.to:
                          related_fields.append((field.name, field.rel.to._meta.app_label.lower(), field.rel.to._meta.object_name.lower()))
                      if hasattr(field.rel, "through") and not field.rel.though._meta.auto_created:
                          related_fields.append((field.name, field.rel.through._meta.app_label.lower(), field.rel.through._meta.object_name.lower()))
              if related_fields:
                  pending_add[app_label, model_name] = related_fields
keep keep keep keep replace replace keep keep keep keep keep
 Stop being overcautious about Field.rel 
django/db/migrations/autodetector.py