Every Help version (you can get there using the documentation link on the top of this page) has an upgrade section. E.g.

https://www.ibm.com/support/knowledgecenter/SSYMRC_6.0.2/com.ibm.jazz.install.doc/topics/c_upgrade_overview.html

In the interactive upgrade Guide https://www.ibm.com/support/knowledgecenter/SSYMRC_6.0.2/com.ibm.jazz.install.doc/topics/roadmap_clm_upgrade.html

 on that page on the top, you find notes about going from previous versions.

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Upgrading to version 6.0.2

Upgrading from version 4 to a version 6 release: Upgrading from version 4 to any release of version 6 is a two-step process. You must first upgrade your server to the latest fix pack of the version 5 release, start the server, ensure that the version 5 upgrade was successful, and then upgrade to the version 6 release. For instructions on upgrading from version 4 to version 5, see the latest version 5 documentation.

z/OS upgrade: For information about upgrading the CLM applications on z/OS®, see Planning to upgrade on z/OS.

Use this guide to upgrade all version 5 and 6 releases of the Rational® solution for Collaborative Lifecycle Management (CLM) applications to version 6.0.2.

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Farther down you have a check box for your specific 5.0.x version check that and if there are specific instructions follow them.

Usually there aren't and you should be able to go from any CLM 5.x to any CLM 6.x but it is necessary to run the interactive upgrade Guide anyway to be sure what the steps are.