Hi, you should not have problems with it, but as a double backup, when you install 8, at login Resolve will see no 8.0 databases, just your 7.0.3 and will ask you if you want to upgrade. I recommend to say no, then use the new database management tools we put into 8 to make a backup of your current databases.
Once that is done, you can then select the 7.0.3 and upgrade it to a 8.0 or 8.0.1 database and all your projects should appear just as they did before. If you get in any trouble, you at least have the backup you made that can be restored.
Peter