diff --git a/acme/acme/client.py b/acme/acme/client.py
index aa7085fb0..f4bc7bf4a 100644
--- a/acme/acme/client.py
+++ b/acme/acme/client.py
@@ -646,12 +646,8 @@ class ClientV2(ClientBase):
             Resource.
 
         """
-        self.net.account = regr  # See certbot/certbot#6258
-        # ACME v2 requires to use a POST-as-GET request (POST an empty JWS) here.
-        # This is done by passing None instead of an empty UpdateRegistration to _post().
-        response = self._post(regr.uri, None)
-        self.net.account = self._regr_from_response(response, uri=regr.uri,
-                                                    terms_of_service=regr.terms_of_service)
+        self.net.account = self._get_v2_account(regr)
+
         return self.net.account
 
     def update_registration(self, regr: messages.RegistrationResource,
@@ -676,7 +672,8 @@ class ClientV2(ClientBase):
         only_existing_reg = regr.body.update(only_return_existing=True)
         response = self._post(self.directory['newAccount'], only_existing_reg)
         updated_uri = response.headers['Location']
-        new_regr = regr.update(uri=updated_uri)
+        new_regr = regr.update(body=messages.Registration.from_json(response.json()),
+                               uri=updated_uri)
         self.net.account = new_regr
         return new_regr
 
diff --git a/acme/tests/client_test.py b/acme/tests/client_test.py
index 27cb49a9e..7ce28b4fe 100644
--- a/acme/tests/client_test.py
+++ b/acme/tests/client_test.py
@@ -140,6 +140,7 @@ class BackwardsCompatibleClientV2Test(ClientTestBase):
         self.response.json.return_value = DIRECTORY_V2.to_json()
         client = self._init()
         self.response.json.return_value = self.regr.body.to_json()
+        self.response.headers = {'Location': 'https://www.letsencrypt-demo.org/acme/reg/1'}
         self.assertEqual(self.regr, client.query_registration(self.regr))
 
     def test_forwarding(self):
diff --git a/certbot/CHANGELOG.md b/certbot/CHANGELOG.md
index f347cc689..d6a6520fc 100644
--- a/certbot/CHANGELOG.md
+++ b/certbot/CHANGELOG.md
@@ -16,7 +16,9 @@ Certbot adheres to [Semantic Versioning](https://semver.org/).
 
 ### Fixed
 
-*
+* The `show_account` now uses the "newAccount" ACME endpoint to fetch the account data, so it
+  doesn't rely on the account URL. This fixes situations where Certbot would use old ACMEv1
+  registration information.
 
 More details about these changes can be found on our GitHub repo.