diff --git a/Gruntfile.js b/Gruntfile.js
index 2f21a82..58218f2 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -171,6 +171,12 @@ module.exports = function(grunt) {
                 },
                 options: browserifyOpt
             },
+            compressionWorker: {
+                files: {
+                    'dist/js/browserbox-compression-worker.browserified.js': ['node_modules/imap-client/node_modules/browserbox/src/browserbox-compression-worker.js']
+                },
+                options: browserifyOpt
+            },
             unitTest: {
                 files: {
                     'test/unit/index.browserified.js': [
@@ -320,6 +326,10 @@ module.exports = function(grunt) {
                 src: ['dist/js/tcp-socket-tls-worker.browserified.js'],
                 dest: 'dist/js/tcp-socket-tls-worker.min.js'
             },
+            compressionWorker: {
+                src: ['dist/js/browserbox-compression-worker.browserified.js'],
+                dest: 'dist/js/browserbox-compression-worker.min.js'
+            },
             unitTest: {
                 src: [
                     'src/lib/underscore/underscore.js',
@@ -403,6 +413,15 @@ module.exports = function(grunt) {
                     sourceMapName: 'dist/js/tcp-socket-tls-worker.min.js.map'
                 }
             },
+            compressionWorker: {
+                files: {
+                    'dist/js/browserbox-compression-worker.min.js': ['dist/js/browserbox-compression-worker.min.js']
+                },
+                options: {
+                    sourceMap: true,
+                    sourceMapName: 'dist/js/browserbox-compression-worker.min.js.map'
+                }
+            },
             options: {
                 banner: '/*! Copyright © <%= grunt.template.today("yyyy") %>, Whiteout Networks GmbH.*/\n'
             }
@@ -588,6 +607,8 @@ module.exports = function(grunt) {
                         'js/mailreader-parser-worker.min.js.map',
                         'js/tcp-socket-tls-worker.browserified.js',
                         'js/tcp-socket-tls-worker.min.js.map',
+                        'js/browserbox-compression-worker.browserified.js',
+                        'js/browserbox-compression-worker.min.js.map',
                         'img/icon-100-ios.png',
                         'img/icon-114-ios.png',
                         'img/icon-120-ios.png',
@@ -662,15 +683,11 @@ module.exports = function(grunt) {
     grunt.registerTask('dist-js-app', [
         'browserify:app',
         'browserify:pbkdf2Worker',
-        'browserify:mailreaderWorker',
-        'browserify:tlsWorker',
         'exorcise:app',
         'ngtemplates',
         'concat:app',
         'concat:readSandbox',
         'concat:pbkdf2Worker',
-        'concat:mailreaderWorker',
-        'concat:tlsWorker',
         'manifest'
     ]);
     grunt.registerTask('dist-js-unitTest', [
diff --git a/package.json b/package.json
index f4e9d60..fbf0b68 100644
--- a/package.json
+++ b/package.json
@@ -62,7 +62,7 @@
     "grunt-svgmin": "~1.0.0",
     "grunt-svgstore": "~0.3.4",
     "iframe-resizer": "^2.8.3",
-    "imap-client": "~0.13.0",
+    "imap-client": "~0.14.0",
     "jquery": "~2.1.1",
     "mailbuild": "^0.3.7",
     "mailreader": "~0.4.0",
diff --git a/src/js/email/email.js b/src/js/email/email.js
index f5e310f..920d0a5 100644
--- a/src/js/email/email.js
+++ b/src/js/email/email.js
@@ -848,6 +848,8 @@ Email.prototype.onConnect = function(imap) {
 
         // tls socket worker path for multithreaded tls in non-native tls environments
         credentials.imap.tlsWorkerPath = config.workerPath + '/tcp-socket-tls-worker.min.js';
+        // enable multithreaded compression handling
+        credentials.imap.compressionWorkerPath = config.workerPath + '/browserbox-compression-worker.min.js';
 
         self._imapClient = (imap || new ImapClient(credentials.imap));