diff --git a/install/installCyberPanel.py b/install/installCyberPanel.py
index 102ce1106..c8fa3ff60 100755
--- a/install/installCyberPanel.py
+++ b/install/installCyberPanel.py
@@ -93,7 +93,7 @@ class InstallCyberPanel:
                 command = 'tar zxf lsws-6.0-ent-x86_64-linux.tar.gz'
                 install.preFlightsChecks.call(command, self.distro, command, command, 1, 1, os.EX_OSERR)
 
-                if str.lower(self.serial) == 'trial':
+                if self.serial.lower() == 'trial':
                     command = 'wget -q --output-document=lsws-6.0/trial.key http://license.litespeedtech.com/reseller/trial.key'
                     install.preFlightsChecks.call(command, self.distro, command, command, 1, 1, os.EX_OSERR)
                 else: