Index: .travis.yml
===================================================================
--- .travis.yml	(revision 44737)
+++ .travis.yml	(working copy)
@@ -16,6 +16,7 @@
     env: WP_TRAVISCI=travis:format
   - php: 7.1
     env: WP_TRAVISCI=travis:js
+  - php: 7.4snapshot
   - php: 7.3
   - php: 7.2
   - php: 7.1
@@ -34,6 +35,7 @@
   - php: nightly
   allow_failures:
   - php: nightly
+  - php: 7.4snapshot
 before_install:
 - |
   if [[ "$WP_TRAVISCI" == "travis:phpunit" ]]; then
@@ -67,7 +69,7 @@
   # Install the specified version of PHPUnit depending on the PHP version:
   if [[ "$WP_TRAVISCI" == "travis:phpunit" ]]; then
     case "$TRAVIS_PHP_VERSION" in
-      7.3|7.2|7.1|nightly)
+     7.4|7.3|7.2|7.1|nightly)
         echo "Using PHPUnit 7.x"
         travis_retry composer global require "phpunit/phpunit:^7"
         ;;