A past employer almost went with this approach, but with a technical audience it's hard to cover all the edge cases with RSS. People get cranky when they get pinged when an article updates superficially, but you also want people updated when the article is basically completely rewritten

Safer to just publish a new article when there's a sufficient amount of content to update. Link the articles together somehow. Maybe add a disclaimer to older (and not updated) articles that they might no longer be valid

Also solves the problem others have mentioned where they don't trust the date on articles. If you have a solid previous article to link to, you're more likely to build trust that the new one really is new