diff --git a/Formula/platformio.rb b/Formula/platformio.rb
index 8b5ac4128080..7faaadd47d6b 100644
--- a/Formula/platformio.rb
+++ b/Formula/platformio.rb
@@ -3,8 +3,8 @@ class Platformio < Formula
 
   desc "Ecosystem for IoT development (Arduino and ARM mbed compatible)"
   homepage "https://platformio.org/"
-  url "https://files.pythonhosted.org/packages/7c/95/899efc1264c63d1ba1d32b4160b2fe3d48020de00f7b8c91dc5b712aa05f/platformio-3.5.2.tar.gz"
-  sha256 "bb311ce5b8f12c95bc45c2071626a4887a3632fb2472b4d69a873b2acfc2e4ec"
+  url "https://files.pythonhosted.org/packages/eb/6f/378c272c27309b3b862b8544dba81f220f682e8fb2155bd142ece4e99c86/platformio-3.5.3.tar.gz"
+  sha256 "21809f0d7e7ab368946dc3b939bca03992bfe3bfeaa759d53107a61b60179ad0"
 
   bottle do
     cellar :any_skip_relocation
@@ -21,8 +21,8 @@ class Platformio < Formula
   end
 
   resource "certifi" do
-    url "https://files.pythonhosted.org/packages/15/d4/2f888fc463d516ff7bf2379a4e9a552fef7f22a94147655d9b1097108248/certifi-2018.1.18.tar.gz"
-    sha256 "edbc3f203427eef571f79a7692bb160a2b0f7ccaa31953e99bd17e307cf63f7d"
+    url "https://files.pythonhosted.org/packages/4d/9c/46e950a6f4d6b4be571ddcae21e7bc846fcbb88f1de3eff0f6dd0a6be55d/certifi-2018.4.16.tar.gz"
+    sha256 "13e698f54293db9f89122b0581843a782ad0934a4fe0172d2a980ba77fc61bb7"
   end
 
   resource "chardet" do