Upgrade 1.3.1.1 to 1.4 stable - general information

[DARKF3D3]

Hi, while i wait the release of PS 1.4 stable i need some information that could help me when i'll do the upgrade to the new PS version.

- Where i can find a guide to make the upgrade?

- It is better if, before the upgrade i make a backup così of all the folder and database?

- If during the upgrade process there will be some problems and errors, if i put all old files PS returns to the older working version?

- During the upgrade process PS show a page with write something, like site in maintenance or the site will be unavailable?

- Which is the modify that remain after the upgrade, i mean mine modification (like custom theme, new module, translation...);



Thanks for the help