diff --git a/src/app/Observers/SignupCodeObserver.php b/src/app/Observers/SignupCodeObserver.php
--- a/src/app/Observers/SignupCodeObserver.php
+++ b/src/app/Observers/SignupCodeObserver.php
@@ -4,6 +4,7 @@
 
 use App\SignupCode;
 use Carbon\Carbon;
+use Illuminate\Support\Str;
 
 class SignupCodeObserver
 {
@@ -26,7 +27,7 @@
 
             // FIXME: Replace this with something race-condition free
             while (true) {
-                $code->code = str_random($code_length);
+                $code->code = Str::random($code_length);
                 if (!SignupCode::find($code->code)) {
                     break;
                 }
diff --git a/src/app/Observers/VerificationCodeObserver.php b/src/app/Observers/VerificationCodeObserver.php
--- a/src/app/Observers/VerificationCodeObserver.php
+++ b/src/app/Observers/VerificationCodeObserver.php
@@ -5,6 +5,7 @@
 use App\VerificationCode;
 use App\SignupCode;
 use Carbon\Carbon;
+use Illuminate\Support\Str;
 
 class VerificationCodeObserver
 {
@@ -27,7 +28,7 @@
 
             // FIXME: Replace this with something race-condition free
             while (true) {
-                $code->code = str_random($code_length);
+                $code->code = Str::random($code_length);
                 if (!VerificationCode::find($code->code)) {
                     break;
                 }
diff --git a/src/app/Traits/UserSettingsTrait.php b/src/app/Traits/UserSettingsTrait.php
--- a/src/app/Traits/UserSettingsTrait.php
+++ b/src/app/Traits/UserSettingsTrait.php
@@ -19,14 +19,19 @@
      *
      * @param string $key Lookup key
      *
-     * @return string
+     * @return string|null
      */
     public function getSetting(string $key)
     {
         $settings = $this->getCache();
-        $value = array_get($settings, $key);
 
-        return ($value !== '') ? $value : null;
+        if (!array_key_exists($key, $settings)) {
+            return null;
+        }
+
+        $value = $settings[$key];
+
+        return empty($value) ? null : $value;
     }
 
     /**
diff --git a/src/composer.json b/src/composer.json
--- a/src/composer.json
+++ b/src/composer.json
@@ -18,9 +18,9 @@
         "doctrine/dbal": "^2.9",
         "fideloper/proxy": "^4.0",
         "geoip2/geoip2": "^2.9",
-        "iatstuti/laravel-nullable-fields": "^1.0",
+        "iatstuti/laravel-nullable-fields": "*",
         "kolab/net_ldap3": "dev-master",
-        "laravel/framework": "5.8.*",
+        "laravel/framework": "6.*",
         "laravel/tinker": "^1.0",
         "silviolleite/laravelpwa": "^1.0",
         "spatie/laravel-translatable": "^4.2",