Some posters worry about the lack of recent updates to Jekyll. Other posters feel Jekyll is mature and feature complete. [1]
How would you define a product as 'feature complete' ?
There is a widespread expectation that a product needs updates to add new features, not just bug fixes. Do you believe that a piece of software can be deemed 'feature complete' without the risk of being seen as stagnant or dead?
[1] RIP Jekyll: https://news.ycombinator.com/item?id=28514029
Different people have different needs. So completeness will always mean different things. You worry about what you need out of it and whether you are getting it.