Do you play with the idea to build something similar to capture all 404's, duplicates and creating and managing SEF url's?
Basically no feature will be lost. SEF URL management is both really complicated and really hard to maintain, which is why I'm putting it alone in 4SEF. Having SEO features and SEF features in sh404SEF really limited what sh404SEF could do in terms of SEO.
As an example, capturing errors: 4SEO already does much more than sh404SEF because it not only record 404s happening on your site but:
- it detects broken links, meaning it tells you "on this page, you have this link /my-blog-post and that one is a 404
- it still records 404s as sh404SEF could do but better, because it's smarter about what to NOT record, avoiding thousands of useless bots-generated errors
- it also records PHP fatal errors, telling you in which component or module the error happened
And lastly, about the error page, next version to be released on Nov 4 (see roadmap) lets you configure error pages so that you can keep your visitors on the site if an error happens. It's both more powerful and much easier to use than on sh404SEF. You can have different pages for different errors (404, 500, 403, etc), in different language, with similar pages suggestions or not (this is all already done, you'll be able to test the development version today or tomorrow).
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