diff --git a/AVRsack/ASBuilder.swift b/AVRsack/ASBuilder.swift
index e34e8b6..4e6adf4 100644
--- a/AVRsack/ASBuilder.swift
+++ b/AVRsack/ASBuilder.swift
@@ -155,8 +155,8 @@ class ASBuilder {
             }
             args          += ["-U", "flash:w:build/"+board+"/"+dir.lastPathComponent!+".hex:i"]
             continuation   = {
-                dispatch_after(dispatch_time(DISPATCH_TIME_NOW, Int64(2*NSEC_PER_SEC)), dispatch_get_main_queue(), {
-                    ASSerialWin.portAvailableAfterUpload(port)
+                DispatchQueue.main.asyncAfter(deadline: .now() + 2.0, execute: {
+                    ASSerialWin.portAvailableAfterUpload(port: port)
                 })
             }
         case .BurnBootloader:
@@ -193,8 +193,8 @@ class ASBuilder {
                     logOut.write(cmdLine.data(using: String.Encoding.utf8, allowLossyConversion: true)!)
                     task2.launch()
                     self.continuation = {
-                        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, Int64(2*NSEC_PER_SEC)), dispatch_get_main_queue(), {
-                            ASSerialWin.portAvailableAfterUpload(port)
+                        DispatchQueue.main.asyncAfter(deadline: .now() + 2.0, execute: {
+                            ASSerialWin.portAvailableAfterUpload(port: port)
                         })
                     }
                 }
diff --git a/AVRsack/ASProjDoc.swift b/AVRsack/ASProjDoc.swift
index f9b0b29..d95553f 100644
--- a/AVRsack/ASProjDoc.swift
+++ b/AVRsack/ASProjDoc.swift
@@ -920,7 +920,7 @@ class ASProjDoc: NSDocument, NSOutlineViewDelegate, NSMenuDelegate, NSOpenSavePa
     @IBAction func uploadProject(sender: AnyObject) {
         builder.continuation = {
             self.selectNodeInOutline(selection: self.files.uploadLog)
-            dispatch_async(dispatch_get_main_queue(), {
+            DispatchQueue.main.async(execute: {
                 self.builder.uploadProject(board: self.board, programmer:self.programmer, port:self.port)
             })
         }
diff --git a/AVRsack/ASSerial.mm b/AVRsack/ASSerial.mm
index fedaba2..c391ec3 100644
--- a/AVRsack/ASSerial.mm
+++ b/AVRsack/ASSerial.mm
@@ -37,14 +37,14 @@ NSString * kASSerialPortsChanged = @"PortsChanged";
     watchSlashDev =
         dispatch_source_create(DISPATCH_SOURCE_TYPE_VNODE, fd, DISPATCH_VNODE_WRITE, dispatch_get_main_queue());
     dispatch_source_set_event_handler(watchSlashDev, ^{
-        [[NotificationCenter defaultCenter] postNotificationName:kASSerialPortsChanged object: nil];
+        [[NSNotificationCenter defaultCenter] postNotificationName:kASSerialPortsChanged object: nil];
     });
     dispatch_resume(watchSlashDev);
 }
 
 + (NSArray<NSString *> *)ports {
     NSMutableArray * cuPorts = [NSMutableArray array];
-    for (NSString * port in [[FileManager defaultManager] contentsOfDirectoryAtPath:@"/dev" error: nil]) {
+    for (NSString * port in [[NSFileManager defaultManager] contentsOfDirectoryAtPath:@"/dev" error: nil]) {
         if ([[port substringToIndex:2] isEqualToString:@"cu"])
             [cuPorts addObject:[port substringFromIndex:3]];
     }
diff --git a/AVRsack/ASSerialWin.swift b/AVRsack/ASSerialWin.swift
index dc0070a..d384a9c 100644
--- a/AVRsack/ASSerialWin.swift
+++ b/AVRsack/ASSerialWin.swift
@@ -161,15 +161,17 @@ class ASSerialWin: NSWindowController {
             serialData  = ""
             logView.setString(serialData)
             readHandle.readabilityHandler = {(handle) in
-                let newData         = handle.availableDataIgnoringExceptions()
-                let newString       = NSString(data: newData, encoding: String.Encoding.ascii) as! String
-                self.serialData    += newString
-                DispatchQueue.main.async(execute: { () -> Void in
-                    self.logView.setString(self.serialData)
-                    if self.scrollToBottom {
-                        self.logView.gotoLine(1000000000, column: 0, animated: true)
-                    }
-                })
+                if let newData = handle.availableDataIgnoringExceptions(),
+                   let newString = String(data: newData, encoding: String.Encoding.ascii)
+                {
+                    self.serialData    += newString
+                    DispatchQueue.main.async(execute: {
+                        self.logView.setString(self.serialData)
+                        if self.scrollToBottom {
+                            self.logView.gotoLine(1000000000, column: 0, animated: true)
+                        }
+                    })
+                }
             }
         }
     }