Just for future reference for those who just encountered the updated FTP_CONNECT function module like I did: table SAPFTP_SERVERS cant be updated via SM30.
Instead, you'll need to update the table directly. This requires the appropriate authorization in the target box and a review of your policies so consider your rules before proceeding with this.
Execute FM SE16N_INTERFACE in SE37 with the following parameters:
I_TAB = SAPFTP_SERVERS
I_EDIT = X
I_SAPEDIT = X
I_DISPLAY = X
You should be able to add (and delete) entries in table SAPFTP_SERVERS. Save and run your custom code to validate.