Reference topic:

It seems that with Commerce you cannot import (convert) legacy subscriptions data, either from when it was an official IPS app or a third party one. This does seem a little odd as Nexus 1.5.9 (on 3.4.x) *will* read the subs data and import it during install.

See ~/nexus/modules_admin/convert/convert.php for specifics.

The only solution to doing this is to install Nexus 1.5.x on board 3.4.x *before* upgrading to IPS4 as it does not appear possible to do this afterwards.

My suggestion is simply to add some code to Commerce to do this if its practical.

Thinking about this a bit more, perhaps this is something that would be more suited to be added to the Converters maybe for IPS4 ?