RMAN Duplicate from lower patchset to higher patchsets

I am sure lot of people might have faced this problem. From what i have researched so far, RMAN does not support duplication (i am not talking restore here, but duplicate clone) between different version of oracle.  

So if you have a very critical system, then obvious thing to do would be upgrade dev, then test , then production. But let's throw another complication into the picture, if lot of your dev and test instances are refreshed from production RMAN backup on a daily basis. Then you can't really upgrade dev/test first and leave production, until your testing is finished. RMAN does not allow duplicating a database from older version to newer version.    

Though there is a procedure to restore database and then upgrade/downgrade  

eg.

restore database;

recover database;

alter database open resetlogs upgrade/downgrade;

now follow the downgrade/upgrade steps;    

As anyone found any way of duplicating database using RMAN from say 10.2.0.3 to 10.2.0.4?  

Regards,
Vishal Gupta    

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