diff --git a/.travis.yml b/.travis.yml
index c20d3c5..49ea5b6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,12 +1,15 @@
+# documentation at https://docs.platformio.org/en/latest/integration/ci/travis.html
+
 language: python
 python:
-    - "2.7"
+    - "3.7"
 
 # Cache PlatformIO packages using Travis CI container-based infrastructure
 sudo: false
 cache:
     directories:
         - "~/.platformio"
+        - $HOME/.cache/pip
 
 env:
     - PLATFORMIO_CI_SRC=examples/SSD1306UiDemo
@@ -19,7 +22,8 @@ env:
 
 install:
     - pip install -U platformio
-    - platformio lib install "paulstoffregen/Time@^1.6"
+    - pio update
+    - platformio lib -g install "paulstoffregen/Time@^1.6"
 
 script:
     - platformio ci --lib="." --board=nodemcuv2