From Wiki

Maintenance Operation and Upgrading Between Versions

It is strongly recommended that you back up your data before attempting any updates or upgrades.

Adding New Modules

IMPORT MODULES

Go to Administration -> Modules management -> Import New Module 

Import the new .zip module or copy the file to addons directory

UPDATE MODULE LIST

Go to Administration -> Modules Management -> Update Module List 

And check what you may want to upgrade and install.

APPLY UPGRADES

Go to Administration -> Modules Management - Apply Upgrades 

If there is a File is not a zip file error then try this:

http://www.openerp.com/forum/topic4214.html?highlight=file%20zip%20file

Server Tools

The server has some tools for maintaining updates:

The server program is located at /usr/lib/tinyerp-server by default.

--init=all (or module for just one module) - This initialises the database 
--update=all (or module for just one module) - This updates the database 

If you want to do an update or init on a selection of modules, you can specify more than one module name as a parameter separated by commas, for example: --update=hr,mrp

The --init=all option recreates all databases specified and ERASES ALL CURRENT DATA previously entered for the specified module. This option should only be used by developers.

For more information take a look at:

tinyerp_server --help

Minor Release Updates

The --update=all updates all database descriptions of all fields and objects, preserving your data. This option is used to automatically update the database when you install new versions. To be more precise, --update does:

1. create new tables
2. create new fields in tables
3. change field type if needed
4. recreate all views and menus
5. recreate all new reports

So, when you change the description of a module or if you install a new version, run the server with --update=all and it will auto-adapt the database to your new version. This is useful for small releases: 2.0, 2.1.0, 2.1.1, 2.2, ... all that has to be done to upgrade your new server and run it (one time) with --update=all.

This works nearly all the time, but you will have trouble in some circumstances: rename of a field is not detected: the program will drop the old field and create the new one. It will work, but you will lose one column of all records in this table. field name conflict: you should not have any conflict, as all names are normalised but never say never ...

We try to avoid these cases in small releases. So, when you install a new minor release, feel free to run --update=all and it will adapt the database preserving your data.

These 2 options are very useful because you never have to create a line of SQL. Every table, row ... are automatically created from the descriptions of objects, reports, views ... It is very easy to maintain.

Major Release Upgrades

Major releases (3.x.x - 4.x.x) may have major database alterations between them. For this purpose, scripts are provided with new major versions to manage the database changes. These can be found in doc/migrate. It is strongly recommended that your database is backed up prior to any attempt at running the upgrade scripts.

1. Stop the old version server
2. Backup your database
3. Run pre.py
4. Start the new version server with --update=all
5. Stop the new version server
6. Run post.py
7. Start the new version server and connect

You may also notice pre-tiny.py and post-tiny.py. In later versions (> 4.2) they have been moved to doc/migrate/tiny. These are examples of customised upgrade scripts and should not be used for a standard upgrade unless this has been advised for your particular case.