Several pages do not work on Asustor NAS after NAS upgrade: "angular.js:12330 TypeError"

I have Duplicati running on an Asustor NAS. This has been working very well until today when I updated my NAS to 4.1.0.RLQ1. Now, the Duplicati web page opens but has no content and none of the buttons work. The JS console is spammed with:

TypeError: Cannot read properties of undefined (reading 'Code')
    at SystemInfo.js?v=
    at angular.js:14567:28
    at n.$eval (angular.js:15846:16)
    at n.$digest (angular.js:15657:15)
    at n.$apply (angular.js:15951:13)
    at l (angular.js:10364:36)
    at F (angular.js:10536:7)
    at K.onload (angular.js:10477:9)

I’ve checked for updates in the Asustor App Central but none were available. I’ve also tried accessing the page from a different browser as well as a private browsing window. The ‘About’ page for Duplicati says I’m running version ‘Unknown’ and the NAS shows version

Any ideas on how to restore functionality?

I have not fixed the issue but have moved to a different backup tool. This post can be deleted or closed.

We should leave it here in case someone else is in the same situation and might offer a solution.

I’m not familiar with this NAS. How was Duplicati installed on it? Is there some sort of package manager on this NAS giving access to some repository? Or did you install from an official Duplicati package?

Found the answer to my question. Judging from the version label you mention, it seems to be a modified package found here in the Asustor App repository.

It can be difficult for us to support modified versions of Duplicati. Maybe the maintainer of this custom version needs to fix something.