Test dropping php 5.5 and upgrading latest codeception

.travis.yml

@@ -1,5 +1,7 @@
 sudo: true
 language: php
+services:
+  - xvfb
 
 env:
   global:
@@ -8,27 +10,15 @@ env:
 matrix:
   fast_finish: true
   include:
-    - php: 5.5
-      dist: trusty
     - php: 5.6
       env: RUN_PHPCS="yes"
-      services:
-        - xvfb
     - php: 7.0
       sudo: true
       addons:
         firefox: 'latest-esr'
-      services:
-        - xvfb
     - php: 7.1
-      services:
-        - xvfb
     - php: 7.2
-      services:
-        - xvfb
     - php: 7.3
-      services:
-        - xvfb
 
 before_script:
 # Forcing localhost in hosts file
@@ -46,10 +36,6 @@ before_script:
 - sudo sed -e "s?%PHPVERSION%?${TRAVIS_PHP_VERSION:0:1}?g" --in-place /etc/apache2/sites-available/default
 - git submodule update --init --recursive
 - sudo service apache2 restart
-# Xvfb on trusty environments (PHP 5.5 and below)
-- if [[ $dist == "trusty" ]]; then export DISPLAY=:99.0; fi
-- if [[ $dist == "trusty" ]]; then sh -e /etc/init.d/xvfb start; fi
-- if [[ $dist == "trusty" ]]; then sleep 3 ; fi # give xvfb some time to start
 # Fluxbox
 - sudo apt-get install fluxbox -y --force-yes
 - fluxbox &

composer.json

@@ -4,14 +4,15 @@
     "license"    : "GPL-2.0+",
     "config": {
         "platform": {
-            "php": "5.5.33"
+            "php": "5.6.0"
         }
     },
     "require"    : {
-        "php": ">=5.4"
+        "php": ">=5.6"
     },
     "require-dev": {
-        "codeception/codeception": "^2.2",
+        "codeception/codeception": "^3",
+        "phpunit/phpunit": "^5.7.27",
         "joomla-projects/joomla-browser": "v3.9.0",
         "consolidation/robo": "^1.0.0",
         "joomla-projects/joomla-testing-robo": "~1.0",