Merge pull request via rest api, version changes

[Elifcan Çakmak]

Hello community,

I'm trying to merge a pull request through rest api using a script. First I get the pull request list that are ready to be merged (looking at some custom criteria), and get the first pull request in the list and send a post request with the version number which I get from the previous get request. But when I try to merge the pull request I get an error as: The remote server returned an error: (409) Conflict. And when I check the version of the pull request, it's getting an older version and that's why the merge fails. 

So my question is how do this pull request version works? Why does it increase in a few seconds between that I'm trying a get request and a post request? Or what am I missing here? 

Do you have any insights? Thanks!

Best,

Elifcan