How to downgrade iOS from 11.3 to 11.2.5 or less without backup?

Nalee7182 wrote:

I’m using iPhone 5s. FYI, I joined the Apple Beta Program. After, I made an upgrade/update on software as it Public Beta from iOS 11.2.5 to 11.3, the phone seems hare wired and some data been deleted or lost. Unfortunately, the backup has been deleted as for replacement new backup purposes. Thus, I cannot do any backup at all after that. Errors starts; i) I cannot log in to my Apple ID (effected to all related features), ii) Some apps ID also effected i.e. dropbox, email, contacts, etc. Hence, any latest information, pictures, contact, cannot be updated. And now I’m using the phone but got afraid I would lost all my latest data as the above. I hope I could get some help from the Support Team or whoever else that can help me to resolve my issues. Thanks.. Nalee, M’sia..

go ask this question in the beta/developer forum, it can't be discussed here.