How do I upgrade from sh404SEF to 4SEF without breaking my website. A detailed explanation is required
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#10211 – How do I upgrade from sh404SEF to 4SEF

Hi
And a detailed explanation is provided in the documentation, including a video.
The most important points of course being that you don't do this on your site but instead on a copy of your site. Once you know how it works and is all tested, you can do the same changes to your real site.
Are you also moving to 4SEO for metadata, redirects, canonical and OpenGraph tags? In that case, documentation is on this page.
Best regards
Yannick Gaultier
weeblr.com / @weeblr