Hi and welcome to the forum!
In my blog post (Manipulating Form Versions section > B.6.c), I noted:
Notice that this template (private version) has the same ID as the one that we sent to our external user (public version). Don’t be confused, this template has a higher version number than the one already sent. As we know, forms will open with the higher version template.
If you've already done that and yet you're still being asked which form template version you wish to open the form with, please check that you have selected automatic upgrade in your Private version by going to Tools > Form Options > Versioning and let me know if you still get the version warning dialogs.
Cheers!