diff --git a/.travis.yml b/.travis.yml
index b84eea2..bda70db 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,9 +7,6 @@ cache:
         - $HOME/.composer/cache/files
 
 php:
-    - 5.4
-    - 5.5
-    - 5.6
     - 7.0
     - 7.1
     - 7.2
@@ -25,13 +22,11 @@ branches:
 matrix:
     fast_finish: true
     include:
-        - php: 5.4
+        - php: 7.0
           env: COMPOSER_FLAGS="--prefer-stable --prefer-lowest" COVERAGE=true TEST_COMMAND="composer test-ci"
-        - php: hhvm
-          dist: trusty
 
 before_install:
-    - if [[ $COVERAGE != true && $TRAVIS_PHP_VERSION != hhvm ]]; then phpenv config-rm xdebug.ini || true; fi
+    - if [[ $COVERAGE != true ]]; then phpenv config-rm xdebug.ini || true; fi
     - travis_retry composer self-update
 
 install:
diff --git a/composer.json b/composer.json
index 9bf58c1..8430530 100644
--- a/composer.json
+++ b/composer.json
@@ -15,7 +15,7 @@
         }
     ],
     "require": {
-        "php": ">=5.4",
+        "php": "^7.0",
         "psr/http-message": "^1.0",
         "php-http/promise": "^1.0"
     },
diff --git a/src/Exception.php b/src/Exception.php
index e7382c3..be15ef3 100644
--- a/src/Exception.php
+++ b/src/Exception.php
@@ -7,6 +7,6 @@
  *
  * @author Márk Sági-Kazár <mark.sagikazar@gmail.com>
  */
-interface Exception
+interface Exception extends \Throwable
 {
 }