data migration steps from RTC 6.0.3 to RTC 6.0.5
Accepted answer
From v603 to v605 may not require OS/DB/Application server change. But it is still the time to check with system requirements and make sure your v603 environments have no problem with v605.
See https://jazz.net/wiki/bin/view/Deployment/DeploymentInstallingUpgradingAndMigrating
then using 605 interactive upgrade guide to generate a detailed procedures for you
https://www.ibm.com/support/knowledgecenter/SSYMRC_6.0.5/com.ibm.jazz.install.doc/topics/roadmap_clm_upgrade.html