Upgrading from 4.7.x-1.* or 4.6.x-* to 4.7.x-2.*
NOTE: Sites that initially installed the 4.7.x-2.* or 5.x-* versions also should not follow any of the instructions on this page.
This documentation is not meant to be a complete guide, since it's unclear at this point how many people actually need to do this.
During the 4.7.x development of the project modules, a fundamental change was made to the code, which resulted in the split between the 4.7.x-1.* and 4.7.x-2.* versions of the module. Previously, project releases were represented via a special table in the database, and all of their behavior was hard-coded into the project.module. Starting with the 4.7.x-2.* series (and all future development), project releases are now represented by release nodes. This was one of the primary changes that made the "new" release system possible (although it is no longer accurate to call the system "new").
As a result, upgrading a project* site from 4.7.x-1.* or 4.6.x-* to 4.7.x-2.* or later can be a complicated task, since the old releases must be converted into release nodes for the release-related functionality to work.
If your site does not use the support for releases, you do not need to worry. In this case, the normal upgrade procedure should be followed (basically: 1) backup, 2) install the new code, 3) run update.php) and everything should work smoothly.
However, if your site started off using project.module 4.7.x-1.* or earlier, and has old releases, you will need to take special care to upgrade to a newer version based on release nodes. To see if your site is affected, query your database and check if the {project_releases} table has any records:
SELECT COUNT(*) FROM project_releases
(if your site uses table prefixing, be sure to include the prefix in the table name).
If you're in the unfortunate case of having to convert old releases into release nodes...
For folks that are confident PHP programmers: You can try the following procedure, which makes use of the script used to upgrade project module for drupal.org. It's recommended that you create a test site which is a copy of the live site you want to upgrade (this will probably take you a few tries, so it's best to have a practice place).
Follow the procedure below:
- Take the site offline
- Follow the normal upgrade procedure
- Make sure you have the latest project and project_issue code, including the
modules/project/releasedirectory for the project_release.module. - Visit your
administer >> modulespage (admin/modules) and enable the "project_release" module. - Edit the
modules/project/release/project_release_update.phpscript included with newer versions of the project.module to suit the needs of your site - Run that script
- Make sure everything worked
- Bring the site back online
This script currently assumes you are using the CVS integration module and that you want to associate releases with CVS tags.
If you're not comfortable trying the above procedure, or you get stuck: Create a support issue in the project.module issue queue. Set the Version to whatever version of 4.7.x-1.* you currently have installed, and set the Component to "Releases".
If you do not have that many releases, and/or, you don't have issues associated with them, you should weigh the cost/benefit of just manually creating new release nodes and writing a simple script to reclassify issue versions accordingly, instead of this elaborate proceedure.

More info to include on this page
There's an unpublished page on drupal.org where I had the todo list for the d.o conversion:
http://drupal.org/node/89783
It contains some other important steps in this procedure that should be folded into this public page. I'm just adding this comment as a reminder to myself, and for hunmonk's benefit so he knows about this other page... We'll get those other instructions folded in soon, definitely before the next round of official releases.
Where's the important "more info" for updating the projects tbls
I'm thinking other folks might actually want to follow these important steps if they're still valid and important.