diff --git a/bedrock/firefox/tests/test_base.py b/bedrock/firefox/tests/test_base.py
index f9771cad724..0d44328858e 100644
--- a/bedrock/firefox/tests/test_base.py
+++ b/bedrock/firefox/tests/test_base.py
@@ -475,6 +475,14 @@ def test_fx_31(self, render_mock):
         template = render_mock.call_args[0][1]
         eq_(template, ['firefox/australis/whatsnew-no-tour.html'])
 
+    @override_settings(DEV=True)
+    def test_rv_prefix(self, render_mock):
+        """Prefixed oldversion shouldn't impact version sniffing."""
+        req = self.rf.get('/en-US/firefox/whatsnew/?oldversion=rv:10.0')
+        self.view(req, fx_version='30.0')
+        template = render_mock.call_args[0][1]
+        eq_(template, ['firefox/australis/whatsnew-tour.html'])
+
     @override_settings(DEV=False)
     def test_fx_australis_secure_redirect(self, render_mock):
         """Should redirect to https: for 29.0."""
@@ -766,6 +774,9 @@ def test_whatsnew_tour_oldversion(self):
         response = self.client.get(self.url + '?oldversion=4.0', HTTP_USER_AGENT=self.user_agent)
         self.assertIn(self.expected, response.content)
 
+        response = self.client.get(self.url + '?oldversion=rv:10.0', HTTP_USER_AGENT=self.user_agent)
+        self.assertIn(self.expected, response.content)
+
         response = self.client.get(self.url + '?oldversion=29.0', HTTP_USER_AGENT=self.user_agent)
         self.assertNotIn(self.expected, response.content)
 
diff --git a/bedrock/firefox/views.py b/bedrock/firefox/views.py
index 88dbbe56a78..a1a5ed80e8a 100644
--- a/bedrock/firefox/views.py
+++ b/bedrock/firefox/views.py
@@ -430,6 +430,9 @@ def get_template_names(self):
         fc_ctx = funnelcake_param(self.request)
         f = fc_ctx.get('funnelcake_id', 0)
         oldversion = self.request.GET.get('oldversion', '')
+        # old versions of Firefox sent a prefixed version
+        if oldversion.startswith('rv:'):
+            oldversion = oldversion[3:]
         versions = ('29.', '30.', '31.')
 
         if version == '29.0a1':