diff --git a/core/client.go b/core/client.go
index adce5b2..f20898a 100644
--- a/core/client.go
+++ b/core/client.go
@@ -1,4 +1,4 @@
-//     Copyright (C) 2020, IrineSistiana
+//     Copyright (C) 2020-2021, IrineSistiana
 //
 //     This file is part of simple-tls.
 //
diff --git a/core/core_test.go b/core/core_test.go
index 494c414..8a9a362 100644
--- a/core/core_test.go
+++ b/core/core_test.go
@@ -1,4 +1,4 @@
-//     Copyright (C) 2020, IrineSistiana
+//     Copyright (C) 2020-2021, IrineSistiana
 //
 //     This file is part of simple-tls.
 //
@@ -83,10 +83,10 @@ func Test_main(t *testing.T) {
 		defer serverListener.Close()
 
 		server := Server{
-			Listener:        serverListener,
-			Dst:             echoListener.Addr().String(),
-			Certificates:    []tls.Certificate{cert},
-			Timeout:         timeout,
+			Listener:     serverListener,
+			Dst:          echoListener.Addr().String(),
+			Certificates: []tls.Certificate{cert},
+			Timeout:      timeout,
 		}
 		go server.ActiveAndServe()
 
diff --git a/core/mode.go b/core/mode.go
index b066458..85b562d 100644
--- a/core/mode.go
+++ b/core/mode.go
@@ -1,4 +1,4 @@
-//     Copyright (C) 2020, IrineSistiana
+//     Copyright (C) 2020-2021, IrineSistiana
 //
 //     This file is part of simple-tls.
 //
diff --git a/core/server.go b/core/server.go
index 6cddbcd..9d0ce3a 100644
--- a/core/server.go
+++ b/core/server.go
@@ -1,4 +1,4 @@
-//     Copyright (C) 2020, IrineSistiana
+//     Copyright (C) 2020-2021, IrineSistiana
 //
 //     This file is part of simple-tls.
 //
diff --git a/core/sip003.go b/core/sip003.go
index c91ce1d..769db25 100644
--- a/core/sip003.go
+++ b/core/sip003.go
@@ -1,4 +1,4 @@
-//     Copyright (C) 2020, IrineSistiana
+//     Copyright (C) 2020-2021, IrineSistiana
 //
 //     This file is part of simple-tls.
 //
diff --git a/core/smux.go b/core/smux.go
index 7ad7c02..7c5444c 100644
--- a/core/smux.go
+++ b/core/smux.go
@@ -1,4 +1,4 @@
-//     Copyright (C) 2020, IrineSistiana
+//     Copyright (C) 2020-2021, IrineSistiana
 //
 //     This file is part of simple-tls.
 //
diff --git a/core/tcp.go b/core/tcp.go
index c0afb51..7b63d0d 100644
--- a/core/tcp.go
+++ b/core/tcp.go
@@ -1,4 +1,4 @@
-//     Copyright (C) 2020, IrineSistiana
+//     Copyright (C) 2020-2021, IrineSistiana
 //
 //     This file is part of simple-tls.
 //
diff --git a/core/tcp_android.go b/core/tcp_android.go
index ea507f3..21b7374 100644
--- a/core/tcp_android.go
+++ b/core/tcp_android.go
@@ -1,6 +1,6 @@
 // +build android
 
-//     Copyright (C) 2020, IrineSistiana
+//     Copyright (C) 2020-2021, IrineSistiana
 //
 //     This file is part of simple-tls.
 //
diff --git a/core/tcp_android_unix.go b/core/tcp_android_unix.go
index 8dc362f..040e666 100644
--- a/core/tcp_android_unix.go
+++ b/core/tcp_android_unix.go
@@ -1,6 +1,6 @@
 // +build linux android
 
-//     Copyright (C) 2020, IrineSistiana
+//     Copyright (C) 2020-2021, IrineSistiana
 //
 //     This file is part of simple-tls.
 //
diff --git a/core/tcp_other.go b/core/tcp_other.go
index a1d56aa..2069150 100644
--- a/core/tcp_other.go
+++ b/core/tcp_other.go
@@ -1,6 +1,6 @@
 // +build !android,!linux
 
-//     Copyright (C) 2020, IrineSistiana
+//     Copyright (C) 2020-2021, IrineSistiana
 //
 //     This file is part of simple-tls.
 //
diff --git a/core/tcp_unix.go b/core/tcp_unix.go
index ca0ae50..9140fa0 100644
--- a/core/tcp_unix.go
+++ b/core/tcp_unix.go
@@ -1,6 +1,6 @@
 // +build linux,!android
 
-//     Copyright (C) 2020, IrineSistiana
+//     Copyright (C) 2020-2021, IrineSistiana
 //
 //     This file is part of simple-tls.
 //
diff --git a/core/utils.go b/core/utils.go
index df598dd..07b76a8 100644
--- a/core/utils.go
+++ b/core/utils.go
@@ -1,4 +1,4 @@
-//     Copyright (C) 2020, IrineSistiana
+//     Copyright (C) 2020-2021, IrineSistiana
 //
 //     This file is part of simple-tls.
 //
diff --git a/main.go b/main.go
index a24200a..f06717d 100644
--- a/main.go
+++ b/main.go
@@ -1,4 +1,4 @@
-//     Copyright (C) 2020, IrineSistiana
+//     Copyright (C) 2020-2021, IrineSistiana
 //
 //     This file is part of simple-tls.
 //