your TOS3.x config wont work.
Well, the migration script should take care of it.
I would suggest to stay on TOS3.x untill the fix reaches HBK and there hopefully should be some LUCI support at that time from openwrt.
Please, don’t discourage users from using migration. Because from your post, it looks like all users would need to have the fix, which is not true.
Here is an article on how you can configure VLANs:
If you need more, then don’t hesitate to reach our technical support department, which is available on tech.support@turris.cz.