diff --git a/lib/ical/serialize.ex b/lib/ical/serialize.ex
index 1341c56..1f43d09 100644
--- a/lib/ical/serialize.ex
+++ b/lib/ical/serialize.ex
@@ -1,6 +1,5 @@
 defmodule ICal.Serialize do
   @moduledoc false
-  use Timex
 
   # Escapes backslashes, commas, semicolons and newlines
   def value(x) when is_binary(x) do
@@ -46,7 +45,8 @@ defmodule ICal.Serialize do
              is_integer(minute) and minute <= 59 and minute >= 0 and
              is_integer(second) and second <= 59 and second >= 0 do
     timestamp
-    |> Timex.to_datetime()
+    |> NaiveDateTime.from_erl!()
+    |> DateTime.from_naive!("Etc/UTC")
     |> value()
   end