I would suggest to remove the unmaintained tag from this extension. I was surprised to find out that the latest master requires MW 1.34 (I am working with 1.31). There have been several commits from the community since the last release 2017...
Topic on Extension talk:VIKI
Appearance
The extension author is no longer working on MediaWiki projects. I do not have the bandwidth to take over maintenance of the extension and have not tried to install it in several years. If there is another developer willing to take it over, that would be great. But, until then, it only gets the "bulk maintenance" changes as @Kghbln mentions.
its a very great extension, it should not get abandoned ;-)
I've always really valued it as well. I'd be interested to hear who is using it.
I am very impressed, tried it for the first time in MW 1.31LTS. It is working out of the box as is!
Yeah, I wrote an earlier version of it then handed it over to Jason. There was so much more we wanted to do with it, but there's only so much time. It would be great to get it working with 1.32+.