Just after we updated many sites to 2.0.6, the development team at automattic brings out 2.0.7 to fix some issues. If you did upgrade to 2.0.6, you don’t have to do all the files:

Development Blog › WordPress 2.0.7
Because this is a much smaller update than previous versions, you do not have to update all of WordPress’ files if you’re upgrading from version 2.0.6. Here is the list of files that have changed since 2.0.6:

* wp-admin/inline-uploading.php
* wp-admin/post.php
* wp-includes/classes.php
* wp-includes/functions.php
* wp-settings.php
* wp-includes/version.php

With 2.1 around the corner- if you are still at 2.0.5 or below- you think, ah, I’ll just go for 2.1- well, guess what: 2.1 changes some basic calls in a big way, so it might not work for everyone. We’ve had it break a large site under development. But, here’s the big news from further in the Dev blog post above:

And just as a reminder, the next major version of WordPress (2.1) is due out by the end of the month, but the 2.0 branch of WordPress will continue to be maintained for several years.

So- if you aren’t able to reconfigure your site to work with 2.1, 2.0 will live on.