diff --git a/src/sources/hits.js b/src/sources/hits.js
index 23586a3fd..553c5b07a 100644
--- a/src/sources/hits.js
+++ b/src/sources/hits.js
@@ -6,7 +6,7 @@ var parseAlgoliaClientVersion = require('../common/parseAlgoliaClientVersion.js'
 
 module.exports = function search(index, params) {
   var algoliaVersion = parseAlgoliaClientVersion(index.as._ua);
-  if (algoliaVersion[0] >= 3 && algoliaVersion[1] > 20) {
+  if (algoliaVersion && algoliaVersion[0] >= 3 && algoliaVersion[1] > 20) {
     params.additionalUA = 'autocomplete.js ' + version;
   }
   return sourceFn;
diff --git a/src/sources/popularIn.js b/src/sources/popularIn.js
index 239d88d53..e720ca669 100644
--- a/src/sources/popularIn.js
+++ b/src/sources/popularIn.js
@@ -6,7 +6,7 @@ var parseAlgoliaClientVersion = require('../common/parseAlgoliaClientVersion.js'
 
 module.exports = function popularIn(index, params, details, options) {
   var algoliaVersion = parseAlgoliaClientVersion(index.as._ua);
-  if (algoliaVersion[0] >= 3 && algoliaVersion[1] > 20) {
+  if (algoliaVersion && algoliaVersion[0] >= 3 && algoliaVersion[1] > 20) {
     params.additionalUA = 'autocomplete.js ' + version;
   }
   if (!details.source) {
@@ -37,6 +37,11 @@ module.exports = function popularIn(index, params, details, options) {
         delete detailsParams.source; // not a query parameter
         delete detailsParams.index; // not a query parameter
 
+        var detailsAlgoliaVersion = parseAlgoliaClientVersion(detailsIndex.as._ua);
+        if (detailsAlgoliaVersion && detailsAlgoliaVersion[0] >= 3 && detailsAlgoliaVersion[1] > 20) {
+          params.additionalUA = 'autocomplete.js ' + version;
+        }
+
         detailsIndex.search(source(first), detailsParams, function(error2, content2) {
           if (error2) {
             _.error(error2.message);
diff --git a/test/unit/popularIn_spec.js b/test/unit/popularIn_spec.js
index c003d89dc..e3e972527 100644
--- a/test/unit/popularIn_spec.js
+++ b/test/unit/popularIn_spec.js
@@ -13,6 +13,9 @@ describe('popularIn', function() {
 
   function build(options) {
     var queries = {
+      as: {
+        _ua: 'javascript wrong agent',
+      },
       search: function(q, params, cb) {
         cb(false, {
           hits: [
@@ -24,6 +27,9 @@ describe('popularIn', function() {
       }
     };
     var products = {
+      as: {
+        _ua: 'javascript wrong agent',
+      },
       search: function(q, params, cb) {
         cb(false, {
           facets: {
@@ -92,6 +98,9 @@ describe('popularIn', function() {
 
   it('should not include the all department entry when no results', function() {
     var queries = {
+      as: {
+        _ua: 'Algolia for vanilla JavaScript 4.3.6'
+      },
       search: function(q, params, cb) {
         cb(false, {
           hits: []
@@ -99,6 +108,9 @@ describe('popularIn', function() {
       }
     };
     var products = {
+      as: {
+        _ua: 'javascript wrong agent',
+      },
       search: function(q, params, cb) {
         throw new Error('Never reached');
       }