What'll be impact of my old ESS Changes, after Upgrade SP13 to SP14?

Hi All,

We want to upgrade the ESS PersInfo with SAP_ESS 100 SP 13 to SAP_ESS 100 SP 14 with EP6.0SP18.

1. So, What will be the impact of my old ESS Customization with ESS PersInfo, will my changes will be present after upgrade?

2. If so is there any way to restore my changes?

3. Do I need to create the New Track for this or old track will work for further customization.

Many Thanks.

Ali