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I have a large body of product support documentation and there are similar pages for each of versions of the product, with minor changes as the product changes. The two oldest versions of this documentation get the best ranking and are powering Google snippets--however, this content is out of date. The team responsible for the support documentation wants current pages to rank higher. I suggested 301 redirects but they want to maintain the old page content for clients still using the older version of the product. Is there a way to move a page's power to a more updated version of the page, but without wiping out the old content? Considering recommending canonical tags, but I'm not sure this will get me all the way there either as there are some differences between pages, especially as the product has changed over time. Thoughts?