diff --git a/polygerrit-ui/app/behaviors/gr-patch-set-behavior/gr-patch-set-behavior.html b/polygerrit-ui/app/behaviors/gr-patch-set-behavior/gr-patch-set-behavior.html
index 25bb545d91..1744364acc 100644
--- a/polygerrit-ui/app/behaviors/gr-patch-set-behavior/gr-patch-set-behavior.html
+++ b/polygerrit-ui/app/behaviors/gr-patch-set-behavior/gr-patch-set-behavior.html
@@ -212,7 +212,7 @@ limitations under the License.
      * Check whether there is no newer patch than the latest patch that was
      * available when this change was loaded.
      *
-     * @return {Promise<boolean>} A promise that yields true if the latest patch
+     * @return {Promise<!Object>} A promise that yields true if the latest patch
      *     has been loaded, and false if a newer patch has been uploaded in the
      *     meantime. The promise is rejected on network error.
      */
@@ -226,7 +226,7 @@ limitations under the License.
             }
             const actualLatest = Gerrit.PatchSetBehavior.computeLatestPatchNum(
                 Gerrit.PatchSetBehavior.computeAllPatchSets(detail));
-            return actualLatest <= knownLatest;
+            return {isLatest: actualLatest <= knownLatest};
           });
     },
 
diff --git a/polygerrit-ui/app/behaviors/gr-patch-set-behavior/gr-patch-set-behavior_test.html b/polygerrit-ui/app/behaviors/gr-patch-set-behavior/gr-patch-set-behavior_test.html
index bad47b99c8..e5adfed99b 100644
--- a/polygerrit-ui/app/behaviors/gr-patch-set-behavior/gr-patch-set-behavior_test.html
+++ b/polygerrit-ui/app/behaviors/gr-patch-set-behavior/gr-patch-set-behavior_test.html
@@ -48,8 +48,8 @@ limitations under the License.
         },
       };
       Gerrit.PatchSetBehavior.fetchIsLatestKnown(knownChange, mockRestApi)
-          .then(isLatest => {
-            assert.isTrue(isLatest);
+          .then(result => {
+            assert.isTrue(result.isLatest);
             done();
           });
     });
@@ -74,8 +74,8 @@ limitations under the License.
         },
       };
       Gerrit.PatchSetBehavior.fetchIsLatestKnown(knownChange, mockRestApi)
-          .then(isLatest => {
-            assert.isFalse(isLatest);
+          .then(result => {
+            assert.isFalse(result.isLatest);
             done();
           });
     });
diff --git a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.js b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.js
index c86c2516f5..ebb5b01a23 100644
--- a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.js
+++ b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.js
@@ -1063,8 +1063,8 @@
       };
 
       return this.fetchIsLatestKnown(this.change, this.$.restAPI)
-          .then(isLatest => {
-            if (!isLatest) {
+          .then(result => {
+            if (!result.isLatest) {
               this.fire('show-alert', {
                 message: 'Cannot set label: a newer patch has been ' +
                     'uploaded to this change.',
diff --git a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html
index a3932c2283..30fc742ec5 100644
--- a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html
+++ b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html
@@ -242,7 +242,7 @@ limitations under the License.
       sandbox.stub(element.$.restAPI, 'getFromProjectLookup')
           .returns(Promise.resolve('test'));
       sandbox.stub(element, 'fetchIsLatestKnown',
-          () => { return Promise.resolve(true); });
+          () => { return Promise.resolve({isLatest: true}); });
       element.change = {
         revisions: {
           rev1: {_number: 1},
@@ -1265,7 +1265,7 @@ limitations under the License.
 
         setup(() => {
           sandbox.stub(element, 'fetchIsLatestKnown')
-              .returns(Promise.resolve(true));
+              .returns(Promise.resolve({isLatest: true}));
           sendStub = sandbox.stub(element.$.restAPI, 'getChangeURLAndSend')
               .returns(Promise.resolve({}));
         });
@@ -1294,7 +1294,7 @@ limitations under the License.
       suite('failure modes', () => {
         test('non-latest', () => {
           sandbox.stub(element, 'fetchIsLatestKnown')
-              .returns(Promise.resolve(false));
+              .returns(Promise.resolve({isLatest: false}));
           const sendStub = sandbox.stub(element.$.restAPI,
               'getChangeURLAndSend');
 
@@ -1308,7 +1308,7 @@ limitations under the License.
 
         test('send fails', () => {
           sandbox.stub(element, 'fetchIsLatestKnown')
-              .returns(Promise.resolve(true));
+              .returns(Promise.resolve({isLatest: true}));
           const sendStub = sandbox.stub(element.$.restAPI,
               'getChangeURLAndSend',
               (num, method, patchNum, endpoint, payload, onErr) => {
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
index a4f621b3dd..1857101466 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
@@ -1242,8 +1242,8 @@
 
       this._updateCheckTimerHandle = this.async(() => {
         this.fetchIsLatestKnown(this._change, this.$.restAPI)
-            .then(latest => {
-              if (latest) {
+            .then(result => {
+              if (result.isLatest) {
                 this._startUpdateCheckTimer();
               } else {
                 this._cancelUpdateCheckTimer();
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
index 7d81f4da90..e784857b66 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
@@ -121,7 +121,7 @@ limitations under the License.
       test('A toggles overlay when logged in', done => {
         sandbox.stub(element, '_getLoggedIn').returns(Promise.resolve(true));
         sandbox.stub(element.$.replyDialog, 'fetchIsLatestKnown')
-            .returns(Promise.resolve(true));
+            .returns(Promise.resolve({isLatest: true}));
         element._change = {labels: {}};
         const openSpy = sandbox.spy(element, '_openReplyDialog');
 
@@ -968,7 +968,7 @@ limitations under the License.
       setup(() => {
         sandbox.stub(element.$.replyDialog, '_draftChanged');
         sandbox.stub(element.$.replyDialog, 'fetchIsLatestKnown',
-            () => { return Promise.resolve(true); });
+            () => { return Promise.resolve({isLatest: true}); });
         element._change = {labels: {}};
       });
 
@@ -1019,7 +1019,7 @@ limitations under the License.
     suite('commit message expand/collapse', () => {
       setup(() => {
         sandbox.stub(element, 'fetchIsLatestKnown',
-            () => { return Promise.resolve(false); });
+            () => { return Promise.resolve({isLatest: false}); });
       });
 
       test('commitCollapseToggle hidden for short commit message', () => {
@@ -1179,7 +1179,7 @@ limitations under the License.
 
         test('_startUpdateCheckTimer up-to-date', () => {
           sandbox.stub(element, 'fetchIsLatestKnown',
-              () => { return Promise.resolve(true); });
+              () => { return Promise.resolve({isLatest: true}); });
 
           element._serverConfig = {change: {update_delay: 12345}};
 
@@ -1190,7 +1190,7 @@ limitations under the License.
 
         test('_startUpdateCheckTimer out-of-date shows an alert', done => {
           sandbox.stub(element, 'fetchIsLatestKnown',
-              () => { return Promise.resolve(false); });
+              () => { return Promise.resolve({isLatest: false}); });
           element.addEventListener('show-alert', () => {
             done();
           });
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog-it_test.html b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog-it_test.html
index babd95c0fb..b3cf2d78a4 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog-it_test.html
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog-it_test.html
@@ -86,7 +86,8 @@ limitations under the License.
         ],
       };
       element.serverConfig = {note_db_enabled: true};
-      sandbox.stub(element, 'fetchIsLatestKnown', () => Promise.resolve(true));
+      sandbox.stub(element, 'fetchIsLatestKnown')
+          .returns(Promise.resolve({isLatest: true}));
     };
 
     setup(() => {
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.js b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.js
index 1830216c86..7d31ebefde 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.js
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.js
@@ -238,8 +238,8 @@
     open(opt_focusTarget) {
       this.knownLatestState = LatestPatchState.CHECKING;
       this.fetchIsLatestKnown(this.change, this.$.restAPI)
-          .then(isUpToDate => {
-            this.knownLatestState = isUpToDate ?
+          .then(result => {
+            this.knownLatestState = result.isLatest ?
                 LatestPatchState.LATEST : LatestPatchState.NOT_LATEST;
           });
 
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.html b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.html
index 3cede6ab51..02bd614cbe 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.html
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.html
@@ -103,8 +103,8 @@ limitations under the License.
       eraseDraftCommentStub = sandbox.stub(element.$.storage,
           'eraseDraftComment');
 
-      sandbox.stub(element, 'fetchIsLatestKnown',
-          () => { return Promise.resolve(true); });
+      sandbox.stub(element, 'fetchIsLatestKnown')
+          .returns(Promise.resolve({isLatest: true}));
 
       // Allow the elements created by dom-repeat to be stamped.
       flushAsynchronousOperations();