So I came across this issue the other day. I had been thrown into updating an existing infopath form with a bunch of custom settings. after making some changes to the form, I published it on our SP 2010 environment and everything worked fine. A few days later I was contacted by a user who had submitted this form a few days prior. Giving the user the 'Form template was created with a newer version of InfoPath' then gives the option to say OK and open in a previous version. OK, OK, Nothing. I looked and looked at it. I had made some additions/subtractions to a few lists the form was pulling from but after looking at the XML, nothing was pulling from any of the lists I made changes to. So after hours of researching online, I still came up with nothing.
For anyone familiar with SharePoint 2010 and InfoPath forms, you already know that publishing works a bit different. Deactivate the solution from the parent site, publish the form as an Admin form, then upload the form into Central Admin InfoPath forms services. So we see that the version is correct.1.0.0.56, 57, 58 and so on.
So again, I had no look with anything online.
FINALLY I FOUND a solution.
1) download a working form from the forms library you are working in and look at the version by opening it as a text copy/or through SP Designer (e.g. - 1.0.0.56)
2) download a copy of the form you are having issues with to your local machine
3) open the form in a txt document and look for the version. (in my case the version was something like 1.0.0.859)
4) Next change the version of the 'troubled copy' to the version of the working copy and save it but save it as the same name it was when you downloaded it.
5) find the location you saved the edited copy and open it. once open, click submit and it will re-submit it to the library. (if you have workflows behind it, it should not affect it, or at least in my case with this form it didn't)
and that is how to fix the
The form template was created with a newer version of InfoPath.
This form template was created by InfoPath version 14.0.0.