J 2.9.10 - VM 3.4.2 - PHP 7.1.26
On one site of mine I upgraded Awo Coupon from 2.5.5 to 18.104.22.168. Since I was not allowed to perform a simple update, I downloaded the most recent version and installed it.
The installation process showed an error. Since then, any attempt to reach the component via the menu in the administration panel was a fail: blank page.
Fortunately, I could restore the previous stage by a backup file.
But is there a safe way to upgrade from 2.5.5 to 22.214.171.124?