--- a/browser/app/profile/firefox.js
+++ b/browser/app/profile/firefox.js
@@ -1804,16 +1804,20 @@ pref("media.gmp-gmpopenh264.provider.ena
 
 pref("browser.apps.URL", "https://marketplace.firefox.com/discovery/");
 
 #ifdef NIGHTLY_BUILD
 pref("browser.polaris.enabled", false);
 pref("privacy.trackingprotection.ui.enabled", false);
 #endif
 
+#ifdef NIGHTLY_BUILD
+pref("browser.tabs.remote.autostart.1", true);
+#endif
+
 // Temporary pref to allow printing in e10s windows on some platforms.
 #ifdef UNIX_BUT_NOT_MAC
 pref("print.enable_e10s_testing", false);
 #else
 pref("print.enable_e10s_testing", true);
 #endif
 
 pref("browser.defaultbrowser.notificationbar", false);

--- a/browser/components/nsBrowserGlue.js
+++ b/browser/components/nsBrowserGlue.js
@@ -2406,17 +2406,17 @@ let DefaultBrowserCheck = {
     }
   },
 };
 
 #ifdef E10S_TESTING_ONLY
 let E10SUINotification = {
   // Increase this number each time we want to roll out an
   // e10s testing period to Nightly users.
-  CURRENT_NOTICE_COUNT: 1,
+  CURRENT_NOTICE_COUNT: 2,
   CURRENT_PROMPT_PREF: "browser.displayedE10SPrompt.1",
   PREVIOUS_PROMPT_PREF: "browser.displayedE10SPrompt",
 
   checkStatus: function() {
     let skipE10sChecks = false;
     try {
       // This order matters, because
       // browser.tabs.remote.autostart.disabled-because-using-a11y is not