We're getting ready to update our site to 1.3.9d from 1.3.8a.

We have decided the best way to do this for us is to rebuild from scratch - main reason being when we first started out a number of modifications were made to core files when installing add ons / customising the site. We therefore want to get a fresh install which will stand up to future upgrades etc.

We created a demo folder and ran the install script - all grand. We then backed up the database from our live site and threw the backup onto the new demo folder (so we can test and play with the demo site with a view to replicating our current one) This immediately propmpted a database upgrade which we have done.

My question is - what exactly does this upgrade do with additional tables created by add ons. Ultimately after testing we will be looking to take the then current 1.3.8a database from the existing site and slot it back into the 1.3.9d - which will prompt for a database upgrade again. Will this upgrade wipe any add ons / amendments to the database which we create in the mean time ?