diff --git a/.travis.yml b/.travis.yml
index 41921e31..459e8526 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,7 +8,8 @@ php:
   - 7.0
   - 7.1
   - 7.2
-  - hhvm # ignore errors, see below
+  - 7.3
+# - hhvm # requires legacy phpunit & ignore errors, see below
 
 # lock distro so new future defaults will not break the build
 dist: trusty
@@ -17,6 +18,8 @@ matrix:
   include:
     - php: 5.3
       dist: precise
+    - php: hhvm
+      install: composer require phpunit/phpunit:^5 --dev --no-interaction
   allow_failures:
     - php: hhvm
 
diff --git a/composer.json b/composer.json
index 40010c2e..7224ae09 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,7 @@
     },
     "require-dev": {
         "clue/block-react": "^1.2",
-        "phpunit/phpunit": "^6.4 || ^5.7 || ^4.8.35"
+        "phpunit/phpunit": "^7.0 || ^6.4 || ^5.7 || ^4.8.35"
     },
     "autoload": {
         "psr-4": { "React\\Dns\\": "src" }
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 13d3fab0..04d426b5 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -8,7 +8,6 @@
          convertWarningsToExceptions="true"
          processIsolation="false"
          stopOnFailure="false"
-         syntaxCheck="false"
          bootstrap="vendor/autoload.php"
 >
     <testsuites>