diff --git a/grunt/sync.js b/grunt/sync.js
index 9308e5892c9eae776365ec8d0903635cfd7813b6..3117f04ffdd2d26e15637e7687415925091741a2 100644
--- a/grunt/sync.js
+++ b/grunt/sync.js
@@ -11,7 +11,12 @@ module.exports = function (grunt) {
     var simpleJsonRequest = require('simple-json-request');
     var semver = require('semver');
     var getJson = function (uri) {
-      return simpleJsonRequest.get({url: uri});
+      grunt.log.debug('Requesting JSON from: ' + uri);
+      return simpleJsonRequest.get({url: uri}).catch(function (e) {
+        grunt.log.fail('Unable to request JSON from:' + uri);
+        grunt.log.fail('(' + e.statusCode + ') ' + e);
+        return [];
+      });
     };
 
     // Internal variables.
@@ -33,10 +38,32 @@ module.exports = function (grunt) {
       grunt.verbose.writeln((expired ? 'EXPIRED' : 'VALID')[expired ? 'red' : 'green']);
     }
 
+    // While the Bootswatch project attempts to maintain version parity with
+    // Bootstrap, it doesn't always happen. This causes issues when the system
+    // expects a 1:1 version match between Bootstrap and Bootswatch.
+    // @see https://github.com/thomaspark/bootswatch/issues/892#ref-issue-410070082
+    var mapVersion = function ($version, $package) {
+      if ($package === 'bootswatch') {
+        switch ($version) {
+          // This version is "broken" because of jsDelivr's API limit.
+          case '3.4.1':
+            $version = '3.4.0';
+            break;
+
+          // This version doesn't exist.
+          case '3.1.1':
+            $version = '3.2.0';
+            break;
+        }
+      }
+      return $version;
+    };
+
     var getApiV1Json = function ($package) {
       var $json = {name: $package, assets: []};
       var $latest = '0.0.0';
       var $versions = [];
+      grunt.log.writeln('Retrieving data for: ' + $package);
       return getJson('https://data.jsdelivr.com/v1/package/npm/' + $package)
         .catch(function (error) {
           if (!(error instanceof Error)) {
@@ -56,7 +83,7 @@ module.exports = function (grunt) {
             if (!$version.match(/^3\.\d+\.\d+$/)) {
               return Promise.resolve();
             }
-            return getJson('https://data.jsdelivr.com/v1/package/npm/' + $package + '@' + $version + '/flat')
+            return getJson('https://data.jsdelivr.com/v1/package/npm/' + $package + '@' + mapVersion($version, $package) + '/flat')
               .then(function ($versionJson) {
                 // Skip empty files.
                 if (!$versionJson.files || !$versionJson.files.length) {
@@ -176,7 +203,7 @@ module.exports = function (grunt) {
         for (var version in libraries[library]) {
           if (!libraries[library].hasOwnProperty(version)) continue;
 
-          var endpoint = library + '#' + version;
+          var endpoint = library + '#' + mapVersion(version, library);
 
           // Check if library is already installed. If so, skip.
           var versionPath = path.join(librariesPath, version);
diff --git a/src/Plugin/Provider/JsDelivr.php b/src/Plugin/Provider/JsDelivr.php
index c538c6f8fbd3fb80e211d828ecbfa8403b366c6e..d85003b7d1c06762c14250c1cda56a1d99e566d5 100644
--- a/src/Plugin/Provider/JsDelivr.php
+++ b/src/Plugin/Provider/JsDelivr.php
@@ -82,8 +82,9 @@ class JsDelivr extends ProviderBase {
     if (!isset($this->themes[$version])) {
       $this->themes[$version] = $this->cacheGet('themes.' . Unicode::escapeDelimiter($version), [], function ($themes) use ($version) {
         foreach (['bootstrap', 'bootswatch'] as $package) {
-          $files = $this->requestApiV1($package, $version);
-          $themes = $this->parseThemes($files, $package, $version, $themes);
+          $mappedVersion = $this->mapVersion($version, $package);
+          $files = $this->requestApiV1($package, $mappedVersion);
+          $themes = $this->parseThemes($files, $package, $mappedVersion, $themes);
         }
         return $themes;
       });
@@ -111,6 +112,30 @@ class JsDelivr extends ProviderBase {
     return $this->versions[$package];
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  protected function mapVersion($version, $package = NULL) {
+    // While the Bootswatch project attempts to maintain version parity with
+    // Bootstrap, it doesn't always happen. This causes issues when the system
+    // expects a 1:1 version match between Bootstrap and Bootswatch.
+    // @see https://github.com/thomaspark/bootswatch/issues/892#ref-issue-410070082
+    if ($package === 'bootswatch') {
+      switch ($version) {
+        // This version is "broken" because of jsDelivr's API limit.
+        case '3.4.1':
+          $version = '3.4.0';
+          break;
+
+        // This version doesn't exist.
+        case '3.1.1':
+          $version = '3.2.0';
+          break;
+      }
+    }
+    return $version;
+  }
+
   /**
    * Parses JSON from the API and retrieves valid files.
    *
diff --git a/src/Plugin/Provider/ProviderBase.php b/src/Plugin/Provider/ProviderBase.php
index a1ca93a0fab4054381505af54142f50cf458e613..b02614a92cf34bec149816e8fe3d9b0c003bd7f3 100644
--- a/src/Plugin/Provider/ProviderBase.php
+++ b/src/Plugin/Provider/ProviderBase.php
@@ -317,6 +317,19 @@ class ProviderBase extends PluginBase implements ProviderInterface {
     return $this->pluginDefinition['versions'];
   }
 
+  /**
+   * Allows providers a way to map a version to a different version.
+   *
+   * @param string $version
+   *   The version to map.
+   *
+   * @return string
+   *   The mapped version.
+   */
+  protected function mapVersion($version) {
+    return $version;
+  }
+
   /**
    * {@inheritdoc}
    */