I got a question, If you uprade to the newest Mybb version and you want to uprade will you lose your database?
No. The information stored in your database is kept.
For more information, please refer to
[Wiki: Upgrading] (Broken link, head over to docs.mybb.com instead).
Of course not, it wouldn't be much of an upgrade if you had to start again every time. You can make backups to revert to in case it goes wrong but it's called an upgrade because it upgrades your current forum to the new version.
Oh, Whats so good about the new uprade?