diff --git a/tests/Functional/Net/SSH2Test.php b/tests/Functional/Net/SSH2Test.php
index 9733b864..f4657cbb 100644
--- a/tests/Functional/Net/SSH2Test.php
+++ b/tests/Functional/Net/SSH2Test.php
@@ -575,7 +575,7 @@ class SSH2Test extends PhpseclibFunctionalTestCase
         $this->assertSame(0, $ssh->getOpenChannelCount());
     }
 
-    public function testKeepAlive(): void
+    public function testKeepAlive()
     {
         $ssh = $this->getSSH2();
         $username = $this->getEnv('SSH_USERNAME');
diff --git a/tests/Unit/Net/SSH2UnitTest.php b/tests/Unit/Net/SSH2UnitTest.php
index 427ae512..0d8a1817 100644
--- a/tests/Unit/Net/SSH2UnitTest.php
+++ b/tests/Unit/Net/SSH2UnitTest.php
@@ -221,7 +221,10 @@ class SSH2UnitTest extends PhpseclibTestCase
         $this->assertEquals(20, $ssh->getTimeout());
     }
 
-    public function testGetStreamTimeout(): void
+    /**
+     * @requires PHPUnit < 10
+     */
+    public function testGetStreamTimeout()
     {
         // no curTimeout, no keepAlive
         $ssh = $this->createSSHMock();