diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.html b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.html
index 42c61477ef..46b803f58f 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.html
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.html
@@ -266,7 +266,7 @@ limitations under the License.
           <span
               id="notLatestLabel"
               hidden$="[[!_isState(knownLatestState, 'not-latest')]]">
-            Patch [[patchNum]] is not latest.
+            [[_computePatchSetWarning(patchNum, _labelsChanged)]]
             <gr-button link on-tap="_reload">Reload</gr-button>
           </span>
         </div>
@@ -279,7 +279,7 @@ limitations under the License.
           <gr-button
               link
               primary
-              disabled="[[_computeSendButtonDisabled(knownLatestState, _sendButtonLabel, diffDrafts, draft, _reviewersMutated, _labelsChanged, _includeComments)]]"
+              disabled="[[_computeSendButtonDisabled(_sendButtonLabel, diffDrafts, draft, _reviewersMutated, _labelsChanged, _includeComments)]]"
               class="action send"
               has-tooltip
               title$="[[_computeSendButtonTooltip(canBeStarted)]]"
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 1a14ae1734..35bdfb0f04 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
@@ -406,12 +406,6 @@
     },
 
     send(includeComments, startReview) {
-      if (this.knownLatestState === 'not-latest') {
-        this.fire('show-alert',
-            {message: 'Cannot reply to non-latest patch.'});
-        return Promise.resolve({});
-      }
-
       const labels = this.$.labelScores.getLabelValues();
 
       const obj = {
@@ -835,16 +829,21 @@
       return savingComments ? 'saving' : '';
     },
 
-    _computeSendButtonDisabled(knownLatestState, buttonLabel, drafts, text,
-        reviewersMutated, labelsChanged, includeComments) {
-      if (this._isState(knownLatestState, LatestPatchState.NOT_LATEST)) {
-        return true;
-      }
+    _computeSendButtonDisabled(buttonLabel, drafts, text, reviewersMutated,
+        labelsChanged, includeComments) {
       if (buttonLabel === ButtonLabels.START_REVIEW) {
         return false;
       }
       const hasDrafts = includeComments && Object.keys(drafts).length;
       return !hasDrafts && !text.length && !reviewersMutated && !labelsChanged;
     },
+
+    _computePatchSetWarning(patchNum, labelsChanged) {
+      let str = `Patch ${patchNum} is not latest.`;
+      if (labelsChanged) {
+        str += ' Voting on a non-latest patch will have no effect.';
+      }
+      return str;
+    },
   });
 })();
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 1b88ec0fb2..8d91ef8fbd 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
@@ -1083,21 +1083,20 @@ limitations under the License.
 
     test('_computeSendButtonDisabled', () => {
       const fn = element._computeSendButtonDisabled.bind(element);
-      assert.isTrue(fn('not-latest'));
-      assert.isFalse(fn('latest', 'Start review'));
-      assert.isTrue(fn('latest', 'Send', {}, '', false, false, false));
+      assert.isFalse(fn('Start review'));
+      assert.isTrue(fn('Send', {}, '', false, false, false));
       // Mock nonempty comment draft array, with seding comments.
-      assert.isFalse(fn('latest', 'Send', {file: ['draft']}, '', false, false,
+      assert.isFalse(fn('Send', {file: ['draft']}, '', false, false,
           true));
       // Mock nonempty comment draft array, without seding comments.
-      assert.isTrue(fn('latest', 'Send', {file: ['draft']}, '', false, false,
+      assert.isTrue(fn('Send', {file: ['draft']}, '', false, false,
           false));
       // Mock nonempty change message.
-      assert.isFalse(fn('latest', 'Send', {}, 'test', false, false, false));
+      assert.isFalse(fn('Send', {}, 'test', false, false, false));
       // Mock reviewers mutated.
-      assert.isFalse(fn('latest', 'Send', {}, '', true, false, false));
+      assert.isFalse(fn('Send', {}, '', true, false, false));
       // Mock labels changed.
-      assert.isFalse(fn('latest', 'Send', {}, '', false, true, false));
+      assert.isFalse(fn('Send', {}, '', false, true, false));
     });
   });
 </script>