You make a change to a working form, save it, and realize a minute later you’ve broken something that was fine before. In version 4, you were on your own. Whatever the form looked like before you saved over it was gone. If you wanted it back, you rebuilt it from memory or from a copy—if you’d thought to make one first. Most of us learned to make those copies the hard way and our file lists filled up with names like ContactForm_backup and ContactForm_backup2.
Version 5 keeps the history for you
The first time you open a form, view, or feed for editing, XMod Pro saves a pristine copy of it. After that, every time you save, it captures another snapshot. So, your file’s history lines up with the moments you actually decided something was worth keeping.

You get to that history from the clock icon in the Control Panel toolbar. It opens in its own tab, with Forms, Views, and Feeds split across the top and every resource listed with how many versions it has. Pick one and its snapshots are laid out by date, newest first, the current one tagged Live and the very first one tagged Original. You can click any snapshot to add a note to it, so “before I rewrote the query” is there waiting for you the next time you come looking.

From there each snapshot gives you a few choices: look at it, compare it against another, restore it, or delete it.
Restore is the one that matters most when you’re in trouble, and it works the way it should. Restoring rolls the file back to that snapshot in place, and it records the rollback as a new version of its own. So going back doesn’t throw away what you’re going back from. If you restore a version and decide that was a mistake too, the version you just left is sitting right there in the history. There’s no way to paint yourself into a corner.
Compare is where this goes past the usual. Pick two versions and XMod Pro shows you what actually changed between them. For most files that’s a side-by-side view of the code with the differences marked, the kind of diff you’d recognize from any developer tool.

For forms built with the Form Builder, you get something better. Instead of making you read raw markup, XMod Pro describes the changes in terms of the form itself: a DropDownList named ddlPublisherID was removed, a DropDownList named pub2 was added, a label changed from one value to another. It’s the difference between reading a diff and being told, in plain language, what’s different about the form. When you’re trying to work out what changed three versions ago, that’s the view you’ll want.

Settings to manage your backups
You’re in control of how much of this XMod Pro keeps.

In the Control Panel settings there’s a Version History section where you can turn the whole thing on or off, keep or skip the pristine original, set how many versions to retain per resource, and optionally age out versions past a certain point. By default it keeps fifty versions per resource and never deletes them by age, and your original copy is held onto no matter how many newer versions come and go.
Backups and versioning are in the public beta now. If you’re a current XMod Pro customer, you can download it from the Downloads section and try it on a test site. The announcement post has the details on requirements, the 90-day expiry, and how to report anything you run into.
Discuss the version 5 beta here