The details of the modifications are there in release notes. The new release is a must download without reading the release notes as there are numerous minor modifications e.g. toggle button between Item invoice and Accounts Invoice , some TDL issues etc.
These rectifications are always subjected to user responses. Whenever a Tally user finds a problem there is a mechanism in Tally by which it can be reported to the company. It would be rectified in next release which is almost after every month.
Any user can talk to Tally representative on its toll free number 1-800-22-8859 Or 1-800-425-8859 and report the bug or send a mail at support at tallysolutions.com.
The new stat version of Tally 9 rel 2.1 which is stat 65 is also to be downloaded as major enhancements related to Bihar VAT has been done. Some minor modifications in Delhi and Kerala states has been done.