No. You don't have to downgrade.

If you would have read this post carefully, you would have found your answer - somebody explaint it in this post on page 5.

Shortly: If you have a Hex-editor program like Ultraedit you can upgrade the application version from 0710 to 0720 in 2 files: lng_rel.tbl and sw_rel.tbl.

The Nav-Computer than will recognize the software as new and will install it.

Kind regard.

Matthias