At wiki.sprachkritik.org I have installed the plugin Post Notification by Email. The email notification works fine for both blog posts and blog/wiki comments, but not for wikis as such (whether newly edited or changed).
I have read your post https://wordpress.org/support/topic/wiki-e-mail-notification-not-working and checked the box "Enable e-mail notifications", but without success. Neither could I find the link "Notify me of changes" in any edited wiki.
I also tried the plugins (1) WP-Mail-SMTP and (2) Easy WP SMTP. However, I don't know how to fill in the settings (which SMTP Host etc).
So I would be grateful for your help!