I would like to know regarding the testing domain, I currently have one licence forum and still working to modify some issues in development mode. Then few months later, the forum will be run publicly soon by users and guests discussions. In order to avoid disturbing the forum process, how do I upgrade the forum offline or online by adding some features or new categories nodes?
Buy new domain for testing with same license which I have now? How do other forumers's message 'It will be back in 15 minutes for upgrading or etc' ?
I completely missed the paragraph about turning it off for adding nodes. But yeah, any administration task can be done (minus upgrading) without turning the board off. Upgraded automatically turns the board off and takes a few minutes at max, so as Brogan said, you'll be fine.
In terms of a testing forum (separate from your production forum), that needs registration turned off and/or password protection to comply with the License Agreement.