Fix reactivate() with Stripe API 2018-02-28 and above

djstripe/models/billing.py

@@ -1152,7 +1152,11 @@ def reactivate(self):
         .. warning:: Reactivating a fully canceled Subscription will fail silently. Be sure to check the returned \
         Subscription's status.
         """
-        return self.update(plan=self.plan)
+        stripe_subscription = self.api_retrieve()
+        stripe_subscription.plan = self.plan.id
+        stripe_subscription.cancel_at_period_end = False
+
+        return Subscription.sync_from_stripe_data(stripe_subscription.save())
 
     def is_period_current(self):
         """ Returns True if this subscription's period is current, false otherwise."""