6.003 to 6.1.5 upgrade

Is there a way to directly upgrade my 6.003 version to 6.1.5 or do I need to upgrade first to 6.004 and so on till I reach 6.1.5 ?

Can I delete the existing files and upload 6.1.5 ? I have around 100 members.

Maybe better to transfer all this manually? )

Can you explain what do you mean by that ?

any help ??

Yes, do it one table at a time.  I don't know for certain this will work all the way back to 6.003, but the general approach would be to back up all your tables one by one in your current installation, and then use the "restore" function in the admin/tool/backup and load those tables into your new system one by one.