Other than hops required by specific frameworks, is there any hop needed for jump from Pega 6 to Pega 8.1. Upgrade guides doenot suggest any limitation as such. Please suggest if any relevant link/article covers this question.
The Pega Platform 8.1 Upgrade guides make reference to steps which are needed for Pega 6 versions. So an upgrade from from Pega 6 can be done.
You should download the guide appropriate for your application server and database server for review.
Additionally, review the information in the Platform Support Guide to understand the impacts such an upgrade may have on your software infrastructure.
However, as my colleague Jakub asks, do you have any Pega frameworks involved as they may have separate requirements.
Also, note that the underlying technology between Pega 6 and Pega 8 has changed quite a bit in some areas. So there may be additional tasks needed to adapt your application should it make use of functionality which has been deprecated or is no longer supported.
Please allow time in your upgrade schedule for any such adaptions that may be revealed.