Upgrade from CRM 2011 to 2013

Hello,

We are in the process of upgrading our CRM 2011 to 2013(eventually will be upgraded to 2016), with the incremental process from 2011 to 2013, I encountered legacy code issue, something like obsolete service end point. Not sure if we can resolve that issue, is there any other way for upgrade? For example, migrate data directly from 2011 to 2013 using some types of data integration tools, such as Scribe, or Kingswaysoft? What options do I have?

Thanks.

Bob