Update of properties does not update version anymore to a previous release

Update properties should never roll back a version. If you have advanced to a newer version and decide to go back, your SCM should be able to assist reverting to the previous version. The update goals are designed to move to newer versions.

Deciding what the previous version could be is actually a lot harder than you would think!

Deciding on the next version and the latest version is a little easier and is helped somewhat by the list of available versions.

We can infer rules about incrementing version numbers, ie 1.0.1.0 has possible next versions of 2.0.0.0, 1.1.0.0, 1.0.2.0, 1.0.1.1. Working backwards is a lot harder programatically, especially when you get down to the 0.0.1 version numbers....

In short, if you need to roll back either use versions:rollback, or scm, or edit by hand to a very early version and run update-properties again

update-properties will only ever modify the pom if it has a newer version to update with

I found the place in the code that prevents this from working as requested. It's a simple one-line change to make it work. It's not a matter of finding the previous version. It's a matter of simply not using a lowerBound on top of the versionRange already in place.

I've attached the fix. It is also available at:
https://github.com/epabst/codehaus-mojo/commit/0e7e9a2511dd6601c43e7257e1ee64f5676958f7

The reason why using SCM to "revert" the change doesn't work well is that other properties in the vicinity may have changed since, so the revert could result in conflicts. The more sure way is to use this plugin and specify the older version.

I would prefer to see a downgradeProperty (and perhaps matching downgrade___ goals too) so that the convention of "upgrade only moves forward" is maintained.