Since there are no release notes and the documentation updating mixed versions for both I figure it may save other some time to know this.
And yes, I know that I should update PHP sooner than later.
Topic on Extension talk:WikiSEO
I've just backported the current code to support PHP 7.0. https://github.com/octfx/wiki-seo/releases/tag/v2.5.0-php7.0 This will be the last Version to support PHP 7.0 though!