is niche edits RIGHT?

[ADAXTZ]

If there is an article link older than my domain, it is very unnatural.

Does Google tolerate this?

 

[HenryObi]

If there is an article link older than my domain, it is very unnatural.

Does Google tolerate this?

It is normal for an author to update their content with new facts and information to make it more relevant. Some of these updates could come in the form of references (links). I don't think it'll pose any serious threat.
If you want good results early go with niche edits. Brand new guest posts won't have as much power as a niche edit on a page that's already ranking.

 

[Kenobii]

It's normal, but the matter is how they changed it

 

[webmasterbd]

People can update their website/blog/resource pages with external anytime they want or feel like it.