You will want to do this in steps (3.unknown -> 6.3 is NOT going to work), and follow the documentation at https://confluence.atlassian.com/display/JIRA/Upgrading+JIRA
There is not a lot more we can tell you - you need to read the documentation, plan the steps of upgrade appropriate for your site and test it.
@Nic Brough [Adaptavist] : Hi Nic,
I have JIRA 3.0 Instance which i have upgraded to 4.4.5 this is upgraded using TAR file on Unix Box, Can you please let me know if i can upgrade the same to 6.3.13 with BIN.
Using same SQL Database and Home and Installation Directory.
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