I am able to Migrate my Old Data from
Magento v-188.8.131.52 to Magento V-2.1.0 using Default Data Migration Tool.
Followed the steps, ignored the fields and tables of Third-Party modules and everything was pretty smooth.
All of the Orders, Settings, Pages etc. are migrated properly except Customers data.
currently 0 customers showing in Magento V-2.1 panel when there are more than 10K customers in reality.
Can someone point me out if I am doing anything wrong? or maybe I ignored a tablename in map file which caused this.