diff --git a/php/domain-validator.php b/php/domain-validator.php
index 5f5ac009..57506b8a 100644
--- a/php/domain-validator.php
+++ b/php/domain-validator.php
@@ -2,11 +2,11 @@
 
 $domain = $_GET['domain'] ?? '';
 
-if (strpos($domain, '.') === false) { 
+if (!str_contains($domain, '.')) { 
     http_response_code(400); 
-} elseif (strpos($domain, '/') !== false) { 
+} elseif (str_contains($domain, '/')) { 
     http_response_code(400);  
-} elseif (strpos($domain, ':') !== false) { 
+} elseif (str_contains($domain, ':')) { 
     http_response_code(400);  
 } elseif (filter_var($domain, FILTER_VALIDATE_DOMAIN, FILTER_FLAG_HOSTNAME) === false) { 
     http_response_code(400); 
diff --git a/php/src/Data/ConfigurationManager.php b/php/src/Data/ConfigurationManager.php
index 69e9bc6e..b2093839 100644
--- a/php/src/Data/ConfigurationManager.php
+++ b/php/src/Data/ConfigurationManager.php
@@ -271,17 +271,17 @@ class ConfigurationManager
      */
     public function SetDomain(string $domain) : void {
         // Validate that at least one dot is contained
-        if (strpos($domain, '.') === false) {
+        if (!str_contains($domain, '.')) {
             throw new InvalidSettingConfigurationException("Domain must contain at least one dot!");
         }
 
         // Validate that no slashes are contained
-        if (strpos($domain, '/') !== false) {
+        if (str_contains($domain, '/')) {
             throw new InvalidSettingConfigurationException("Domain must not contain slashes!");
         }
 
         // Validate that no colons are contained
-        if (strpos($domain, ':') !== false) {
+        if (str_contains($domain, ':')) {
             throw new InvalidSettingConfigurationException("Domain must not contain colons!");
         }