--- a/browser/extensions/e10srollout/bootstrap.js
+++ b/browser/extensions/e10srollout/bootstrap.js
@@ -6,23 +6,29 @@
 
 const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
 
 Cu.import("resource://gre/modules/Preferences.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/UpdateUtils.jsm");
 Cu.import("resource://gre/modules/AppConstants.jsm");
 
- // The amount of people to be part of e10s
+// The amount of people to be part of e10s
 const TEST_THRESHOLD = {
   "beta": 0.9,  // 90%
   "release": 1.0,  // 100%
   "esr": 1.0,  // 100%
 };
 
+// If a user qualifies for the e10s-multi experiement, this is how many
+// content processes to use.
+const MULTI_BUCKETS = {
+  "beta": { 1: .5, 4: 1, },
+};
+
 const ADDON_ROLLOUT_POLICY = {
   "beta": "50allmpc",
   "release": "50allmpc",
   "esr": "esrA", // WebExtensions and Addons with mpc=true
 };
 
 if (AppConstants.RELEASE_OR_BETA) {
   // Bug 1348576 - e10s is never enabled for non-official release builds
@@ -115,24 +121,24 @@ function defineCohort() {
 
   let cohortPrefix = "";
   if (disqualified) {
     cohortPrefix = "disqualified-";
   } else if (hasNonExemptAddon) {
     cohortPrefix = `addons-set${addonPolicy}-`;
   }
 
-  let inMultiExperiment = false;
+  let eligibleForMulti = false;
   if (userOptedOut.e10s || userOptedOut.multi) {
     // If we detected that the user opted out either for multi or e10s, then
     // the proper prefs must already be set.
     setCohort("optedOut");
   } else if (userOptedIn.e10s) {
     setCohort("optedIn");
-    inMultiExperiment = true;
+    eligibleForMulti = true;
   } else if (temporaryDisqualification != "") {
     // Users who are disqualified by the backend (from multiprocessBlockPolicy)
     // can be put into either the test or control groups, because e10s will
     // still be denied by the backend, which is useful so that the E10S_STATUS
     // telemetry probe can be correctly set.
 
     // For these volatile disqualification reasons, however, we must not try
     // to activate e10s because the backend doesn't know about it. E10S_STATUS
@@ -142,63 +148,58 @@ function defineCohort() {
     Preferences.reset(PREF_E10S_PROCESSCOUNT + ".web");
   } else if (!disqualified && testThreshold < 1.0 &&
              temporaryQualification != "") {
     // Users who are qualified for e10s and on channels where some population
     // would not receive e10s can be pushed into e10s anyway via a temporary
     // qualification which overrides the user sample value when non-empty.
     setCohort(`temp-qualified-${temporaryQualification}`);
     Preferences.set(PREF_TOGGLE_E10S, true);
-    inMultiExperiment = true;
+    eligibleForMulti = true;
   } else if (testGroup) {
     setCohort(`${cohortPrefix}test`);
     Preferences.set(PREF_TOGGLE_E10S, true);
-    inMultiExperiment = true;
+    eligibleForMulti = true;
   } else {
     setCohort(`${cohortPrefix}control`);
     Preferences.reset(PREF_TOGGLE_E10S);
     Preferences.reset(PREF_E10S_PROCESSCOUNT + ".web");
   }
 
   // Now determine if this user should be in the e10s-multi experiment.
-  // - We only run the experiment on the beta channel.
+  // - We only run the experiment on channels defined in MULTI_BUCKETS.
   // - We decided above whether this user qualifies for the experiment.
   // - If the user already opted into multi, then their prefs are already set
   //   correctly, we're done.
   // - If the user has addons that disqualify them for multi, leave them with
   //   the default number of content processes (1 on beta) but still in the
   //   test cohort.
-  if (updateChannel !== "beta" ||
-      !inMultiExperiment ||
+  if (!(updateChannel in MULTI_BUCKETS) ||
+      !eligibleForMulti ||
       userOptedIn.multi ||
       disqualified ||
       getAddonsDisqualifyForMulti()) {
     Preferences.reset(PREF_E10S_PROCESSCOUNT + ".web");
     return;
   }
 
   // If we got here with a cohortPrefix, it must be "addons-set50allmpc-",
   // and we know because of getAddonsDisqualifyForMulti that the addons that
   // are installed must be web extensions.
   if (cohortPrefix) {
     cohortPrefix = "webextensions-";
   }
 
   // The user is in the multi experiment!
   // Decide how many content processes to use for this user.
-  let BUCKETS = {
-    1: .25,
-    2: .5,
-    4: .75,
-    8: 1
-  };
+  let buckets = MULTI_BUCKETS[updateChannel];
 
   let multiUserSample = getUserSample(true);
-  for (let sampleName of Object.getOwnPropertyNames(BUCKETS)) {
-    if (multiUserSample < BUCKETS[sampleName]) {
+  for (let sampleName of Object.getOwnPropertyNames(buckets)) {
+    if (multiUserSample < buckets[sampleName]) {
       setCohort(`${cohortPrefix}multiBucket${sampleName}`);
       Preferences.set(PREF_E10S_PROCESSCOUNT + ".web", sampleName);
       break;
     }
   }
 }
 
 function shutdown(data, reason) {

--- a/browser/extensions/e10srollout/install.rdf.in
+++ b/browser/extensions/e10srollout/install.rdf.in
@@ -5,17 +5,17 @@
 
 #filter substitution
 
 <RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
      xmlns:em="http://www.mozilla.org/2004/em-rdf#">
 
   <Description about="urn:mozilla:install-manifest">
     <em:id>e10srollout@mozilla.org</em:id>
-    <em:version>1.15</em:version>
+    <em:version>1.50</em:version>
     <em:type>2</em:type>
     <em:bootstrap>true</em:bootstrap>
     <em:multiprocessCompatible>true</em:multiprocessCompatible>
 
     <!-- Target Application this theme can install into,
         with minimum and maximum supported versions. -->
     <em:targetApplication>
       <Description>