diff --git a/factories/esSearcherFactory.js b/factories/esSearcherFactory.js
index fa32d34..ea9ad31 100644
--- a/factories/esSearcherFactory.js
+++ b/factories/esSearcherFactory.js
@@ -225,7 +225,7 @@
       // Eg. with params:     /_search?size=5&from=5
       //esUrlSvc.setParams(uri, self.pagerArgs);
 
-      var headers = esUrlSvc.getHeaders(uri);
+      var headers = esUrlSvc.getHeaders(uri, self.config.customHeaders);
 
       activeQueries.count++;
       return transport.query(url, queryDslWithPagerArgs, headers)
@@ -287,6 +287,7 @@
         queryText:  otherQuery,
         config:     {
           apiMethod:    'POST',
+          customHeaders: self.config.customHeaders,
           numberOfRows: self.config.numberOfRows,
           version:      self.config.version,
         },
@@ -334,7 +335,7 @@
       var self    = this;
       var uri     = esUrlSvc.parseUrl(self.url);
       var url     = esUrlSvc.buildExplainUrl(uri, doc);
-      var headers = esUrlSvc.getHeaders(uri);
+      var headers = esUrlSvc.getHeaders(uri, self.config.customHeaders);
 
       return $http.post(url, { query: self.queryDsl.query }, {headers: headers})
         .then(function(response) {
diff --git a/factories/searcherFactory.js b/factories/searcherFactory.js
index 39b3d10..722e823 100644
--- a/factories/searcherFactory.js
+++ b/factories/searcherFactory.js
@@ -18,6 +18,7 @@
       self.queryText          = options.queryText;
       self.config             = options.config;
       self.type               = options.type;
+      self.customHeaders      = options.customHeaders;
 
       self.docs               = [];
       self.grouped            = {};
diff --git a/factories/settingsValidatorFactory.js b/factories/settingsValidatorFactory.js
index 336590b..9279c43 100644
--- a/factories/settingsValidatorFactory.js
+++ b/factories/settingsValidatorFactory.js
@@ -14,10 +14,11 @@
     var Validator = function(settings) {
       var self  = this;
 
-      self.searchUrl    = settings.searchUrl;
-      self.searchEngine = settings.searchEngine;
-      self.apiMethod    = settings.apiMethod;
-      self.version      = settings.version;
+      self.searchUrl      = settings.searchUrl;
+      self.searchEngine   = settings.searchEngine;
+      self.apiMethod      = settings.apiMethod;
+      self.version        = settings.version;
+      self.customHeaders  = settings.customHeaders;
 
       self.searcher = null;
       self.fields   = [];
@@ -45,7 +46,8 @@
           '',
           {
             version: self.version,
-            apiMethod: self.apiMethod
+            apiMethod: self.apiMethod,
+            customHeaders: self.customHeaders
           },
           self.searchEngine
         );
diff --git a/package.json b/package.json
index d549930..d7ee61a 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "splainer-search",
-  "version": "2.19.0",
+  "version": "2.20.0",
   "main": "splainer-search.js",
   "authors": [
     "Doug Turnbull <dturnbull@opensourceconnections.com>",
diff --git a/services/esUrlSvc.js b/services/esUrlSvc.js
index 163c8ba..2067155 100644
--- a/services/esUrlSvc.js
+++ b/services/esUrlSvc.js
@@ -63,13 +63,18 @@ angular.module('o19s.splainer-search')
        * for an ES document.
        *
        */
-      function buildDocUrl (uri, doc) {
+      function buildDocUrl (uri, doc, addExplain) {
         var index = doc._index;
         var type  = doc._type;
         var id    = doc._id;
 
         var url = self.buildBaseUrl(uri);
-        url = url + '/' + index + '/' + type + '/' + id;
+
+        if (type) {
+          url = url + '/' + index + '/' + type + '/' + id + (addExplain ? '/_explain' : '');
+        } else {
+          url = url + '/' + index + '/' + (addExplain ? '_explain/' : '') + id;
+        }
 
         return url;
       }
@@ -80,13 +85,12 @@ angular.module('o19s.splainer-search')
        * Builds ES URL of the form [protocol]://[host][:port]/[index]/[type]/[id]/_explain
        * for an ES document.
        *
+       * For newer versions of ES the format has changed as doc types are deprecated:
+       * [protocol]://[host][:port]/[index]/_explain/[id]
+       *
        */
       function buildExplainUrl (uri, doc) {
-        var docUrl = self.buildDocUrl(uri, doc);
-
-        var url = docUrl + '/_explain';
-
-        return url;
+        return buildDocUrl(uri, doc, true);
       }
 
       /**
@@ -142,10 +146,14 @@ angular.module('o19s.splainer-search')
         uri.params = params;
       }
 
-      function getHeaders (uri) {
+      function getHeaders (uri, customHeaders) {
         var headers = {};
+        customHeaders = customHeaders || '';
 
-        if ( angular.isDefined(uri.username) && uri.username !== '' &&
+        if (customHeaders.length > 0) {
+          // TODO: Validate before saving? Or throw exception when this is called
+          headers = JSON.parse(customHeaders);
+        } else if ( angular.isDefined(uri.username) && uri.username !== '' &&
           angular.isDefined(uri.password) && uri.password !== '') {
           var authorization = 'Basic ' + btoa(uri.username + ':' + uri.password);
           headers = { 'Authorization': authorization };
@@ -157,7 +165,7 @@ angular.module('o19s.splainer-search')
       function isBulkCall (uri) {
         return uri.pathname.endsWith('_msearch');
       }
-      
+
       function isTemplateCall (uri) {
         return uri.pathname.endsWith('_search/template');
       }