No official date for the moment, but expect it really soon
It is good news, but a good motto for phone manufacturers is to under-promise and over-deliver.
Be prepared for Android 8 to have new bugs you need to fix....
I would create a separate forum for Android 8 versions so problems there can be tracked separately, and I would continue working out solutions to Android 7 bugs here in the meantime. The BV8000 Pro is a great phone and a lot of the teething bugs have been fixed. Some remain. You are on the verge of having a near perfect rugged phone on Android 7....if you keep the bug fixes coming it will continue to sell well, and deservedly so.
I for one won't be upgrading to Android 8 until I've seen the bug reports....