diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 8b31e23..0b83fff 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -10,7 +10,7 @@ jobs:
 
     strategy:
       matrix:
-        php-version: ['5.6', '7.0', '7.1', '7.2', '7.3', '7.4', '8.0']
+        php-version: ['5.6', '7.0', '7.1', '7.2', '7.3', '7.4', '8.0', '8.1']
 
     steps:
     - uses: actions/checkout@v2
diff --git a/lib/TwoFactorAuth.php b/lib/TwoFactorAuth.php
index c46ac17..c94f806 100644
--- a/lib/TwoFactorAuth.php
+++ b/lib/TwoFactorAuth.php
@@ -272,7 +272,7 @@ public function getQRText($label, $secret)
     {
         return 'otpauth://totp/' . rawurlencode($label)
             . '?secret=' . rawurlencode($secret)
-            . '&issuer=' . rawurlencode($this->issuer)
+            . '&issuer=' . rawurlencode((string)$this->issuer)
             . '&period=' . intval($this->period)
             . '&algorithm=' . rawurlencode(strtoupper($this->algorithm))
             . '&digits=' . intval($this->digits);