I sometimes read the posts in the MySQL Newsgroup (mailing.database.mysql) and take a look if there are any questions where I can help other MySQL users. That's a good think for many purposes: I can help people, I can learn new things for myself and last but not least - there are often questions that give me interesting material for this weblog. Such as this:
There was a question, how to update to the latest MySQL 5.0 version - not only from 4.1 (which is described perfectly in the MySQL manual), but also from older versions like 3.23. Here's how I would do it:
* make a dump of all your data except the mysql database
* make a separate dump of the mysql database
* uninstall this old MySQL version
* install the latest MySQL version from scratch
* create a separate database for the previously dumped mysql database (e.g.
mysql_old) and restore this dump
* sync the old mysql database with the new one (this might require some
manual work, because the structures will be slightly different)
* when the new mysql database is OK, restore the dump of the data
If you have a chance, try to install the new version on a separate machine,
before you uninstall the old MySQL version to make sure that everythink works.