diff --git a/www/js/app.js b/www/js/app.js
index 05bd1ac9..72d1b2ea 100644
--- a/www/js/app.js
+++ b/www/js/app.js
@@ -2616,7 +2616,7 @@ define(['jquery', 'zimArchiveLoader', 'uiUtil', 'util', 'utf8', 'images', 'cooki
                             });
                         }
                     };
-                    state.selectedArchive.getDirEntryByTitle(title).then(readFile).fail(function (err) {
+                    state.selectedArchive.getDirEntryByTitle(title).then(readFile).catch(function (err) {
                         console.error('Failed to read ' + title, err);
                         messagePort.postMessage({
                             'action': 'giveContent',
@@ -2935,7 +2935,7 @@ define(['jquery', 'zimArchiveLoader', 'uiUtil', 'util', 'utf8', 'images', 'cooki
                                         cssBlobCache.set(newURL[0], newURL[1]);
                                     injectCSS(); //DO NOT move this: it must run within .then function to pass correct values
                                 });
-                        }).fail(function (e) {
+                        }).catch(function (e) {
                             console.error("could not find DirEntry for CSS : " + title, e);
                             //@TODO Change this to push an array of [title, title] afters simplified code in injectCSS()
                             blobArray.push(title);
@@ -3473,7 +3473,7 @@ define(['jquery', 'zimArchiveLoader', 'uiUtil', 'util', 'utf8', 'images', 'cooki
                             uiUtil.feedNodeWithBlob(script, 'src', content, 'text/javascript', params.allowHTMLExtraction);
                         });
                     }
-                }).fail(function (e) {
+                }).catch(function (e) {
                     console.error("could not find DirEntry for javascript : " + title, e);
                 });
             });
@@ -3537,7 +3537,7 @@ define(['jquery', 'zimArchiveLoader', 'uiUtil', 'util', 'utf8', 'images', 'cooki
                     $('.alert').hide();
                     readArticle(dirEntry);
                 }
-            }).fail(function () {
+            }).catch(function () {
                 console.error("Error reading article with title " + title);
                 if (params.appIsLaunching) goToMainArticle();
                 // Line below prevents bootloop
diff --git a/www/js/lib/filecache.js b/www/js/lib/filecache.js
index d086deb3..073c048a 100644
--- a/www/js/lib/filecache.js
+++ b/www/js/lib/filecache.js
@@ -144,16 +144,16 @@ define(['q'], function(Q) {
         });
     };
     var readInternal = function(file, begin, end) {
-        var deferred = Q.defer();
-        var reader = new FileReader();
-        reader.onload = function(e) {
-            deferred.resolve(new Uint8Array(e.target.result));
-        };
-        reader.onerror = reader.onabort = function(e) {
-            deferred.reject(e);
-        };
-        reader.readAsArrayBuffer(file.slice(begin, end));
-        return deferred.promise;
+        return Q.Promise(function(resolve, reject) {
+            var reader = new FileReader();
+            reader.readAsArrayBuffer(file.slice(begin, end));
+            reader.onload = function(e) {
+                resolve(new Uint8Array(e.target.result));
+            };
+            reader.onerror = reader.onabort = function(e) {
+                reject(e);
+            };
+        });
     };
 
     return {
diff --git a/www/js/lib/images.js b/www/js/lib/images.js
index f9cb04ba..bd65f4c4 100644
--- a/www/js/lib/images.js
+++ b/www/js/lib/images.js
@@ -94,7 +94,7 @@ define(['uiUtil'], function (uiUtil) {
                     image.style.transition = 'opacity 0.5s ease-in';
                     image.style.opacity = '1';
                 });
-            }).fail(function (e) {
+            }).catch(function (e) {
                 console.error('Could not find DirEntry for image: ' + title, e);
                 checkBatch();
             });
diff --git a/www/js/lib/zimArchive.js b/www/js/lib/zimArchive.js
index afce3447..57a04e0a 100644
--- a/www/js/lib/zimArchive.js
+++ b/www/js/lib/zimArchive.js
@@ -315,7 +315,7 @@ define(['zimfile', 'zimDirEntry', 'util', 'utf8'],
                     callback(data);
                 });
             }
-        }).fail(function (e) {
+        }).catch(function (e) {
             console.warn("Metadata with key " + key + " not found in the archive", e);
             callback();
         });
diff --git a/www/js/lib/zimfile.js b/www/js/lib/zimfile.js
index c5d6d337..93270a64 100644
--- a/www/js/lib/zimfile.js
+++ b/www/js/lib/zimfile.js
@@ -241,7 +241,7 @@ define(['xzdec_wrapper', 'util', 'utf8', 'q', 'zimDirEntry'], function(xz, util,
                 }
             }
             return typeMap;
-        }).fail(function(err) {
+        }).catch(function(err) {
             console.error('Unable to read MIME type list', err);
             return new Map;
         });