Participate in the db4o community and help to improve db4o. The main community website for db4o is http://developer.db4o.com. There you can find the db4o forums, blog posts additional resources and the newest db4o releases.
The best place to ask questions about db4o, discuss and make suggestions are the db4o forums. You can find the db4o forums here:http://developer.db4o.com/Forums.aspx
There's a overview of additional resources here: http://developer.db4o.com/Resources.aspx To stay informed about new features, community activity and other news subscribe to the different db4o blogs: http://developer.db4o.com/Blogs.aspx.
Or follow us on Twitter: http://twitter.com/db4objects
Every software contains bugs and so does db4o. If you find bugs please report them to us. In case you're not sure if you really found a bug, you maybe want to discuss your issue first on the db4o forum. As soon as you're sure that you found a bug it best to report in our bug-tracking system. The login is the same as in the db4o forums. Read more on tips and tricks for reporting bugs here.
When possible include a small test program which reproduces the issue with the bug report. A test case avoids confusion and effort to reproduce the bug.