diff --git a/.travis.yml b/.travis.yml
index 2401067..d698be1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,10 +1,10 @@
 language: php
 php:
-- 5.5
 - 5.6
 - 7.0
 - 7.1
 - 7.2
+- 7.3
 sudo: false
 before_script:
 - composer self-update
@@ -21,5 +21,5 @@ deploy:
   project: xray-p3k-io
   on:
     branch: master
-    php: 5.5
+    php: 7.2
   keyfile: XRay-67d8fdd0bba3.json
diff --git a/app.yaml b/app.yaml
index b0a78dc..838a2de 100644
--- a/app.yaml
+++ b/app.yaml
@@ -1,4 +1,4 @@
-runtime: php55
+runtime: php72
 api_version: 1
 handlers:
 - url: /assets