In my file functions_autotaggerfromcontentandtitle.php the lines were:

line 85
return split(',', $csv);

line 13
return split(' ', $text);

but I changed the world split to explode in both lines:

line 85
return explode(',', $csv);

line 13
return explode(' ', $text);

and seems to work now! without error in PhP 7 and the tags are being added.

Thanks!

Installed on 4.2.3 and it seems to work.
However, after a testing, the plugin added automatically only tags from post body.
The opposite of what happened here:
Nothing added from the title, despite the fact that used many different words.

Is there any customization that should be also done?

-update- this issue only appears when on title are used words other than in English language

Interesting, mind giving us a url?

I am not sure if this has to do with it, but ever since we
installed the most recent Node.js version of 14.5.0 on the server and confirmed it's accessible for both the root user as well as the other users.

[root@host ~]# node -v
v14.5.0

[______@host ~]$ node -v
v14.5.0

now all attempts to post a URL in a forum post result in a 504 bad gateway error. This bad gateway error is happening only at my vbulletin 4 site (that is running this mod), it is not happening when URLs are posted in posts at my vbulletin 5 forums.