for the latest NS 6.8 version the download page contains the NS 6.7 sums both for MD5 and SHA1.
The mirrors do have the 6.8 sum files but there is a mismatch.
I believe that for a linux server release trust is very important aspect to consider: nobody must install a version not fulfilling this minimal sum checks. The release process must provide this for all versions, including the NS 7.alpha…
I would completely remove the download link to NS7 during alpha stage. I see a lot of people here start using it on production and then ask for support… I’m afraid they’re wasting a lot of time!