7zip attachment problem

[S474N]

Have problem with add 7z to Attachment. The same problem as this:
http://community.mybb.com/thread-26925.html

MIME type: application/x-7z-compressed (tried also "application/zip" or "application/octet-stream")

On FTP is file OK. When downloaded from forum, there is another size of file:
original (and also on FTP) - 683.191
downloaded - 683.076

[.m.]

application/x-7z-compressed should work ! check it once again.

[S474N]

Tested more times and nothing

[.m.]

^ assuming that you have a legit forum (see support eligibility policy)
would you like to PM me temporary access to forum admin panel to check it

[S474N]

Some news?