Error upgrading from 4.1.3.1 to 4.1.8.1

[infernonrx]

Trying to upgrade right now and it's giving me this strange error:  Fatal error: Undefined constant 'IPS\TEST_DELTA_ZIP' in /home4/infernonr1/public_html/applications/core/modules/admin/system/upgrade.php on line 99

Anyone know what this is about? 

[stoo2000]

11 minutes ago, infernonrx said:

Trying to upgrade right now and it's giving me this strange error:  Fatal error: Undefined constant 'IPS\TEST_DELTA_ZIP' in /home4/infernonr1/public_html/applications/core/modules/admin/system/upgrade.php on line 99

Anyone know what this is about?

That error suggests that you don't have the latest files, I would recommend re-downloading 4.1.8.1 from the client area, re-upload ALL files and then try again.

[infernonrx]

Will do, I appreciate the response