If you want to upgrade your Jira instance from very old version to the latest one then you will have to perform several jumps. I am trying to list the versions that you need to upgrade to.
5.2.7 or 6.0.3 > 6.4.14 > 7.0.11 > 7.13.13 > 8.15.0 > Cloud
For each version you will have to ensure the platform is support as well - mainly Java and Database. You can find this information for 8.15 here.
Hopefully this will help you.
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