Currently I am using "Index1" for "sourcetype1". I want to change this "sourcetype1" to a new index "Index2". I made changes in the inputs.conf under splunkhome/etc/deployment-apps/appname/local in the deployment server and restarted Splunk, but still the "sourcetype1" is not indexing to "Index2". May I know whether I am missing something, or is it mandatory to go into the remote server and do changes in the Splunk forwarder..
Two things here
1) Yes, you would need to update the inputs.conf on the forwarder (using deployment server if you use one) to update the index for the sourcetype for future events.
2) Historical data would still be stored under older index.