CRM-ISA CONFLICT RESOLUTION after the Support Packs

Hi

We are planning to upgrade our CRM-ISA environment from SP11 to SP19. I came to know that we will face some conflicts.since we made some custom modification to the earlier package. Is there any documentation available how

to resolve these conflicts through NWDS?

I can create one track for SP11 and another for SP19.

Thanks

Prasad