diff --git a/models/models.go b/models/models.go
index 96683f2..e7325d2 100644
--- a/models/models.go
+++ b/models/models.go
@@ -51,6 +51,15 @@ type DirectoryInfo struct {
 
 	// set to true if the value counts are accurate
 	AccurateCounts bool
+
+	// Caps contains the backend capabilities
+	Caps *Capabilities
+}
+
+// Capabilities provides the backend capabilities
+type Capabilities struct {
+	Sort   bool
+	Thread bool
 }
 
 // A MessageInfo holds information about the structure of a message
diff --git a/worker/imap/checkmail.go b/worker/imap/checkmail.go
index d9dcfd3..57af3af 100644
--- a/worker/imap/checkmail.go
+++ b/worker/imap/checkmail.go
@@ -31,6 +31,7 @@ func (w *IMAPWorker) handleCheckMailMessage(msg *types.CheckMail) {
 					Exists: int(status.Messages),
 					Recent: int(status.Recent),
 					Unseen: int(status.Unseen),
+					Caps:   w.caps,
 				},
 				SkipSort: true,
 			}, nil)
diff --git a/worker/imap/worker.go b/worker/imap/worker.go
index 7debd88..3ed646d 100644
--- a/worker/imap/worker.go
+++ b/worker/imap/worker.go
@@ -66,6 +66,8 @@ type IMAPWorker struct {
 	idler    *idler
 	observer *observer
 	cache    *leveldb.DB
+
+	caps *models.Capabilities
 }
 
 func NewIMAPWorker(worker *types.Worker) (types.Backend, error) {
@@ -75,6 +77,7 @@ func NewIMAPWorker(worker *types.Worker) (types.Backend, error) {
 		selected: &imap.MailboxStatus{},
 		idler:    newIdler(imapConfig{}, worker),
 		observer: newObserver(imapConfig{}, worker),
+		caps:     &models.Capabilities{},
 	}, nil
 }
 
@@ -83,6 +86,16 @@ func (w *IMAPWorker) newClient(c *client.Client) {
 	w.client = &imapClient{c, sortthread.NewThreadClient(c), sortthread.NewSortClient(c)}
 	w.idler.SetClient(w.client)
 	w.observer.SetClient(w.client)
+	sort, err := w.client.sort.SupportSort()
+	if err == nil && sort {
+		w.caps.Sort = true
+		w.worker.Logger.Println("Server Capability found: Sort")
+	}
+	thread, err := w.client.thread.SupportThread()
+	if err == nil && thread {
+		w.caps.Thread = true
+		w.worker.Logger.Println("Server Capability found: Thread")
+	}
 }
 
 func (w *IMAPWorker) handleMessage(msg types.WorkerMessage) error {
@@ -226,6 +239,7 @@ func (w *IMAPWorker) handleImapUpdate(update client.Update) {
 				Exists: int(status.Messages),
 				Recent: int(status.Recent),
 				Unseen: int(status.Unseen),
+				Caps:   w.caps,
 			},
 		}, nil)
 	case *client.MessageUpdate:
diff --git a/worker/maildir/worker.go b/worker/maildir/worker.go
index cf2970e..0862838 100644
--- a/worker/maildir/worker.go
+++ b/worker/maildir/worker.go
@@ -186,6 +186,11 @@ func (w *Worker) getDirectoryInfo(name string) *models.DirectoryInfo {
 		Unseen: 0,
 
 		AccurateCounts: false,
+
+		Caps: &models.Capabilities{
+			Sort:   true,
+			Thread: false,
+		},
 	}
 
 	dir := w.c.Dir(name)
diff --git a/worker/notmuch/worker.go b/worker/notmuch/worker.go
index 51e8298..35e6840 100644
--- a/worker/notmuch/worker.go
+++ b/worker/notmuch/worker.go
@@ -228,6 +228,11 @@ func (w *worker) gatherDirectoryInfo(name string, query string) (
 			// total unread
 			Unseen:         count.Unread,
 			AccurateCounts: true,
+
+			Caps: &models.Capabilities{
+				Sort:   true,
+				Thread: true,
+			},
 		},
 	}
 	return info, nil