Older versions of Medilink would always sort referrals in the order that they were entered. That meant that sometimes newer referrals would be out of order when your edited or added in a new referral for an existing referrer.
Note the order of the screenshot below where we have been able to put in a very old referral, but it is now the default selected referral (because it was the last one entered in).
In 2017 R2 we have added an option to sort referrals by date so that the most recent referrals are first. This is in File Menu -> General Options -> Sort Referrals by Date (4th col towards the bottom).
This means that the most recent referral dates will be first, and the selections will choose this most recent referral by default.