InfoPath Dev

The Infopath forms are emailed to different users. They fill and submit it and save a copy locally for future updates. The users do not want to goto sharepoint site at all to pull up new copy everytime. Now, if 2 users get the same copy, the second user submits his/her changes it will go and overwrite the first user's change. How does one solve this type of concurrency and mismatch issue? Is there a way so that the second one can get a notification that the data changed and option to either refresh data or overwrite?

You need to write code that queries it and looks at the version number and if it is greater displays a message.

Patrick Halstead:

You need to write code that queries it and looks at the version number and if it is greater displays a message.

 And this should be made on submissions and against server considering that the same form can be opened at different times?

According to this post a form linked to a published (into Sharepoint) template cannot be opened by more than one user.

Is it correct?