diff --git a/.travis.yml b/.travis.yml
index 485fcf6e..8e831308 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -12,38 +12,26 @@ env:
 matrix:
   fast_finish: true
   include:
-    - php: 5.6
-      env:
-        - DEPS=lowest
-    - php: 5.6
-      env:
-        - DEPS=latest
-    - php: 7
-      env:
-        - DEPS=lowest
-    - php: 7
-      env:
-        - DEPS=latest
-    - php: 7.1
+    - php: 7.3
       env:
         - DEPS=lowest
-    - php: 7.1
+    - php: 7.3
       env:
         - DEPS=latest
-        - CS_CHECK=true
-        - TEST_COVERAGE=true
-    - php: 7.2
+    - php: 7.4
       env:
         - DEPS=lowest
-    - php: 7.2
+    - php: 7.4
       env:
         - DEPS=latest
-    - php: 7.3
+    - php: nightly
       env:
         - DEPS=lowest
-    - php: 7.3
+        - COMPOSER_ARGS="--no-interaction --ignore-platform-reqs"
+    - php: nightly
       env:
         - DEPS=latest
+        - COMPOSER_ARGS="--no-interaction --ignore-platform-reqs"
 
 before_install:
   - if [[ $TEST_COVERAGE != 'true' ]]; then phpenv config-rm xdebug.ini || return 0 ; fi
diff --git a/composer.json b/composer.json
index 30169547..10dee6f8 100644
--- a/composer.json
+++ b/composer.json
@@ -21,12 +21,16 @@
     "extra": {
     },
     "require": {
-        "php": "^5.6 || ^7.0",
+        "php": "^7.3 || ~8.0.0",
         "laminas/laminas-zendframework-bridge": "^1.0"
     },
+    "suggest": {
+        "ext-iconv": "*",
+        "ext-mbstring": "*"
+    },
     "require-dev": {
         "laminas/laminas-coding-standard": "~1.0.0",
-        "phpunit/phpunit": "^5.7.27 || ^6.5.8 || ^7.1.2"
+        "phpunit/phpunit": "^9.3"
     },
     "autoload": {
         "psr-4": {
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 8a578f4b..2553b969 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -3,15 +3,14 @@
          xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
          bootstrap="vendor/autoload.php"
          colors="true">
+    <coverage processUncoveredFiles="true">
+        <include>
+            <directory suffix=".php">./src</directory>
+        </include>
+    </coverage>
     <testsuites>
         <testsuite name="laminas-escaper Test Suite">
             <directory>./test</directory>
         </testsuite>
     </testsuites>
-
-    <filter>
-        <whitelist processUncoveredFilesFromWhitelist="true">
-            <directory suffix=".php">./src</directory>
-        </whitelist>
-    </filter>
 </phpunit>
diff --git a/test/EscaperTest.php b/test/EscaperTest.php
index 3b043b4a..732e7efa 100644
--- a/test/EscaperTest.php
+++ b/test/EscaperTest.php
@@ -9,6 +9,7 @@
 namespace LaminasTest\Escaper;
 
 use Laminas\Escaper\Escaper;
+use Laminas\Escaper\Exception\InvalidArgumentException;
 use PHPUnit\Framework\TestCase;
 
 class EscaperTest extends TestCase
@@ -174,25 +175,23 @@ class EscaperTest extends TestCase
      */
     protected $escaper;
 
-    public function setUp()
+    protected function setUp(): void
     {
         $this->escaper = new Escaper('UTF-8');
     }
 
-    /**
-     * @expectedException \Laminas\Escaper\Exception\InvalidArgumentException
-     * @expectedExceptionMessage Laminas\Escaper\Escaper constructor parameter must be a string, received integer
-     */
     public function testSettingEncodingToNonStringShouldThrowException()
     {
-        $escaper = new Escaper(1);
+        $this->expectExceptionMessage(
+            "Laminas\Escaper\Escaper constructor parameter must be a string, received integer"
+        );
+        $this->expectException(InvalidArgumentException::class);
+        new Escaper(1);
     }
 
-    /**
-     * @expectedException \Laminas\Escaper\Exception\InvalidArgumentException
-     */
     public function testSettingEncodingToEmptyStringShouldThrowException()
     {
+        $this->expectException(InvalidArgumentException::class);
         new Escaper('');
     }
 
@@ -207,7 +206,7 @@ public function testSettingValidEncodingShouldNotThrowExceptions()
 
     public function testSettingEncodingToInvalidValueShouldThrowException()
     {
-        $this->expectException(\Laminas\Escaper\Exception\InvalidArgumentException::class);
+        $this->expectException(InvalidArgumentException::class);
         new Escaper('invalid-encoding');
     }