S4HC 2002 release : Document Type Enhancement and Impact on Reversal Document type

Dear colleagues,

Concerning this enhancement and whatever option taken by the customer, I have a doubt regarding past reversal document types, transacted before 2002 upgrade:

Will these transactions be kept in the database with historical values, meaning as they were when performed? For instance I did a KA reversal in January 2020, how can I find this KA reversal after the upgrade? Will I need to look for a KA reversal done in January, or will this Jan transaction be kept as anything different in the future after upgrade?

Regards,

Axel