diff --git a/composer.json b/composer.json
index 4990dd29c..7db9426c2 100755
--- a/composer.json
+++ b/composer.json
@@ -8,6 +8,7 @@
     ],
     "type": "silverstripe-vendormodule",
     "require": {
+        "php": "^7.3 || ^8.0",
         "silverstripe/cms": "^4.0",
         "silverstripe/lumberjack": "^2.0",
         "silverstripe/tagfield": "^2.0",
@@ -15,7 +16,7 @@
         "silverstripe/asset-admin": "^1.0"
     },
     "require-dev": {
-        "sminnee/phpunit": "^5.7",
+        "phpunit/phpunit": "^9.5",
         "squizlabs/php_codesniffer": "^3.0"
     },
     "extra": {
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 052f7c360..6a309c412 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,8 +1,9 @@
 <phpunit bootstrap="vendor/silverstripe/cms/tests/bootstrap.php" colors="true">
-    <testsuite name="blog">
-        <directory>tests/</directory>
-    </testsuite>
-
+    <testsuites>
+        <testsuite name="blog">
+            <directory>tests/</directory>
+        </testsuite>
+    </testsuites>
     <filter>
         <whitelist addUncoveredFilesFromWhitelist="true">
             <directory suffix=".php">src/</directory>
diff --git a/tests/BlogCategoryTest.php b/tests/BlogCategoryTest.php
index 1cc4aa089..321bec552 100755
--- a/tests/BlogCategoryTest.php
+++ b/tests/BlogCategoryTest.php
@@ -13,9 +13,6 @@
 use SilverStripe\Security\Member;
 use SilverStripe\Security\Security;
 
-/**
- * @mixin PHPUnit_Framework_TestCase
- */
 class BlogCategoryTest extends FunctionalTest
 {
     /**
@@ -26,7 +23,7 @@ class BlogCategoryTest extends FunctionalTest
     /**
      * {@inheritdoc}
      */
-    public function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
 
@@ -36,7 +33,7 @@ public function setUp()
     /**
      * {@inheritdoc}
      */
-    public function tearDown()
+    protected function tearDown(): void
     {
         DBDatetime::clear_mock_now();
 
diff --git a/tests/BlogFunctionalTest.php b/tests/BlogFunctionalTest.php
index aae2ddbd4..505486a23 100644
--- a/tests/BlogFunctionalTest.php
+++ b/tests/BlogFunctionalTest.php
@@ -13,7 +13,7 @@ class BlogFunctionalTest extends FunctionalTest
 
     protected static $use_draft_site = true;
 
-    protected function setUp()
+    protected function setUp(): void
     {
         Config::modify()->set(URLSegmentFilter::class, 'default_allow_multibyte', true);
         i18n::set_locale('fa_IR');
@@ -33,7 +33,7 @@ public function testMemberProfileWithMultibyteUrlAndName()
         $result = $this->get(rawurlencode('آبید') . '/profile/' . rawurlencode('عبّاس-آبان'));
 
         $this->assertEquals(200, $result->getStatusCode());
-        $this->assertContains('My Blog Post', $result->getBody());
+        $this->assertStringContainsString('My Blog Post', $result->getBody());
     }
 
     public function testMemberProfileWithMultibyteUrlAndEnglishName()
@@ -41,6 +41,6 @@ public function testMemberProfileWithMultibyteUrlAndEnglishName()
         $result = $this->get(rawurlencode('آبید') . '/profile/bob-jones');
 
         $this->assertEquals(200, $result->getStatusCode());
-        $this->assertContains('My Blog Post', $result->getBody());
+        $this->assertStringContainsString('My Blog Post', $result->getBody());
     }
 }
diff --git a/tests/BlogPostFilterTest.php b/tests/BlogPostFilterTest.php
index 708c68095..d9eb19149 100755
--- a/tests/BlogPostFilterTest.php
+++ b/tests/BlogPostFilterTest.php
@@ -8,7 +8,6 @@
 use SilverStripe\Security\Security;
 
 /**
- * @mixin PHPUnit_Framework_TestCase
  * @coversDefaultClass \SilverStripe\Blog\Model\BlogPostFilter
  */
 class BlogPostFilterTest extends SapphireTest
@@ -18,14 +17,14 @@ class BlogPostFilterTest extends SapphireTest
      */
     protected static $fixture_file = 'blog.yml';
 
-    public function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
 
         DBDatetime::set_mock_now('2013-10-10 20:00:00');
     }
 
-    public function tearDown()
+    protected function tearDown(): void
     {
         DBDatetime::clear_mock_now();
 
diff --git a/tests/BlogPostTest.php b/tests/BlogPostTest.php
index 44391948e..90e6333da 100644
--- a/tests/BlogPostTest.php
+++ b/tests/BlogPostTest.php
@@ -13,7 +13,7 @@ class BlogPostTest extends SapphireTest
 {
     protected static $fixture_file = 'blog.yml';
 
-    protected function tearDown()
+    protected function tearDown(): void
     {
         DBDatetime::clear_mock_now();
         parent::tearDown();
@@ -159,7 +159,7 @@ public function testGetMonthlyArchiveLink($type, $expected)
         $blogPost = $this->objFromFixture(BlogPost::class, 'FirstBlogPost');
 
         $archiveLink = $blogPost->getMonthlyArchiveLink($type);
-        $this->assertContains('archive/', $archiveLink);
+        $this->assertStringContainsString('archive/', $archiveLink);
         $this->assertStringEndsWith($expected, $archiveLink);
     }
 
@@ -181,7 +181,7 @@ public function testGetYearlyArchiveLink()
         $blogPost = $this->objFromFixture(BlogPost::class, 'FirstBlogPost');
 
         $archiveLink = $blogPost->getYearlyArchiveLink();
-        $this->assertContains('archive/', $archiveLink);
+        $this->assertStringContainsString('archive/', $archiveLink);
         $this->assertStringEndsWith('/2013', $archiveLink);
     }
 }
diff --git a/tests/BlogTagTest.php b/tests/BlogTagTest.php
index 88a48ff29..ca024813b 100755
--- a/tests/BlogTagTest.php
+++ b/tests/BlogTagTest.php
@@ -2,7 +2,6 @@
 
 namespace SilverStripe\Blog\Tests;
 
-use PHPUnit_Framework_TestCase;
 use SilverStripe\Blog\Model\Blog;
 use SilverStripe\Blog\Model\BlogPost;
 use SilverStripe\Blog\Model\BlogTag;
@@ -13,21 +12,18 @@
 use SilverStripe\Security\Member;
 use SilverStripe\Security\Security;
 
-/**
- * @mixin PHPUnit_Framework_TestCase
- */
 class BlogTagTest extends FunctionalTest
 {
     protected static $fixture_file = 'blog.yml';
 
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
 
         DBDatetime::set_mock_now('2013-10-10 20:00:00');
     }
 
-    protected function tearDown()
+    protected function tearDown(): void
     {
         DBDatetime::clear_mock_now();
 
diff --git a/tests/BlogTest.php b/tests/BlogTest.php
index 4792f5977..a02f65e12 100755
--- a/tests/BlogTest.php
+++ b/tests/BlogTest.php
@@ -2,7 +2,7 @@
 
 namespace SilverStripe\Blog\Tests;
 
-use PHPUnit_Framework_TestCase;
+use SilverStripe\Control\HTTPResponse_Exception;
 use SilverStripe\Blog\Model\Blog;
 use SilverStripe\Blog\Model\BlogController;
 use SilverStripe\Blog\Model\BlogPost;
@@ -17,14 +17,11 @@
 use SilverStripe\ORM\SS_List;
 use SilverStripe\Security\Member;
 
-/**
- * @mixin PHPUnit_Framework_TestCase
- */
 class BlogTest extends SapphireTest
 {
     protected static $fixture_file = 'blog.yml';
 
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
 
@@ -37,7 +34,7 @@ protected function setUp()
         $blog->publishRecursive();
     }
 
-    protected function tearDown()
+    protected function tearDown(): void
     {
         DBDatetime::clear_mock_now();
 
@@ -327,12 +324,10 @@ public function testFilteredCategoriesArchive()
         );
     }
 
-    /**
-     * @expectedException \SilverStripe\Control\HTTPResponse_Exception
-     * @expectedExceptionCode 404
-     */
     public function testDisabledProfiles()
     {
+        $this->expectException(HTTPResponse_Exception::class);
+        $this->expectExceptionCode(404);
         Config::modify()->set(BlogController::class, 'disable_profiles', true);
 
         $controller = BlogController::create();
diff --git a/tests/Model/BlogControllerFunctionalTest.php b/tests/Model/BlogControllerFunctionalTest.php
index c188bcbd2..39385a652 100644
--- a/tests/Model/BlogControllerFunctionalTest.php
+++ b/tests/Model/BlogControllerFunctionalTest.php
@@ -13,7 +13,7 @@ class BlogControllerFunctionalTest extends FunctionalTest
 
     protected static $use_draft_site = true;
 
-    protected function setUp()
+    protected function setUp(): void
     {
         Config::modify()->set(URLSegmentFilter::class, 'default_allow_multibyte', true);
         i18n::set_locale('fa_IR');
@@ -26,7 +26,7 @@ public function testGetCategoriesWithMultibyteUrl()
         $result = $this->get('my-blog/category/' . rawurlencode('آبید'));
 
         $this->assertEquals(200, $result->getStatusCode());
-        $this->assertContains('آبید', $result->getBody());
+        $this->assertStringContainsString('آبید', $result->getBody());
     }
 
     public function testGetTagsWithMultibyteUrl()
@@ -34,6 +34,6 @@ public function testGetTagsWithMultibyteUrl()
         $result = $this->get('my-blog/tag/' . rawurlencode('برتراند'));
 
         $this->assertEquals(200, $result->getStatusCode());
-        $this->assertContains('برتراند', $result->getBody());
+        $this->assertStringContainsString('برتراند', $result->getBody());
     }
 }
diff --git a/tests/Widgets/BlogArchiveWidgetTest.php b/tests/Widgets/BlogArchiveWidgetTest.php
index 767d18f6a..6e4f79391 100644
--- a/tests/Widgets/BlogArchiveWidgetTest.php
+++ b/tests/Widgets/BlogArchiveWidgetTest.php
@@ -15,7 +15,7 @@ class BlogArchiveWidgetTest extends SapphireTest
 {
     protected static $fixture_file = 'BlogArchiveWidgetTest.yml';
 
-    protected function setUp()
+    protected function setUp(): void
     {
         if (!class_exists(Widget::class)) {
             self::$fixture_file = null;
@@ -28,7 +28,7 @@ protected function setUp()
         parent::setUp();
     }
 
-    protected function tearDown()
+    protected function tearDown(): void
     {
         parent::tearDown();