diff --git a/src/ProcessManager/FirefoxManager.php b/src/ProcessManager/FirefoxManager.php
index 7114a70a..c92ff0b4 100644
--- a/src/ProcessManager/FirefoxManager.php
+++ b/src/ProcessManager/FirefoxManager.php
@@ -53,19 +53,23 @@ public function start(): WebDriver
             $this->waitUntilReady($this->process, $url.$this->options['path'], 'firefox');
         }
 
-        $capabilities = DesiredCapabilities::firefox();
-
-        /** @var FirefoxOptions $firefoxOptions */
-        $firefoxOptions = $capabilities->getCapability(FirefoxOptions::CAPABILITY);
+        $firefoxOptions = [];
         if (isset($_SERVER['PANTHER_FIREFOX_BINARY'])) {
-            $firefoxOptions->setOption('binary', $_SERVER['PANTHER_FIREFOX_BINARY']);
+            $firefoxOptions['binary'] = $_SERVER['PANTHER_FIREFOX_BINARY'];
         }
         if ($this->arguments) {
-            $firefoxOptions->addArguments($this->arguments);
+            $firefoxOptions['args'] = $this->arguments;
         }
+
+        $capabilities = DesiredCapabilities::firefox();
+        $capabilities->setCapability('moz:firefoxOptions', $firefoxOptions);
+
         // Prefer reduced motion, see https://developer.mozilla.org/fr/docs/Web/CSS/@media/prefers-reduced-motion
         if ($_SERVER['PANTHER_REDUCED_MOTION'] ?? false) {
-            $firefoxOptions->setPreference('ui.prefersReducedMotion', 'reduced');
+            /** @var FirefoxOptions|array $firefoxOptions */
+            $firefoxOptions = $capabilities->getCapability(FirefoxOptions::CAPABILITY) ?? [];
+            $firefoxOptions = $firefoxOptions instanceof FirefoxOptions ? $firefoxOptions->toArray() : $firefoxOptions;
+            $firefoxOptions['prefs']['ui.prefersReducedMotion'] = 'reduced';
         }
 
         foreach ($this->options['capabilities'] as $capability => $value) {