Your package only needs to be registered once. The versions are drawn from your Git tags. From the Bower documentation:
Your package must be available at a Git endpoint (e.g., GitHub); remember to push your Git tags!
Not to worry, I had no idea what this meant either. After poking around a bit, I stumbled across this.
Here's the quick and easy way to solve your problem... from your project's root directory run:
% git tag v1.0.4
If you type:
% git tag
you'll see the version you just created. Now push your Git tags:
% git push origin v1.0.4
Now when you run bower info angular-backstretch-adrr
, you'll see the version you just pushed.