Downgrade RPD 11.1.1.6 to 11.1.1.5 Version

While opening 11.1.1.6 Version of RPD Using 11.1.1.5 Version Admin tool, Will get below error msg.

To avoid such kind of error you need to downgrade the RPD. There is repository downgrade utility nqgenoldverrpd.exe file available into 
C:\Oracle\Oracle_BI1\bifoundation\server\bin>nqgenoldverrpd

Syntax:
nqgenoldverrpd   -P repository_password  -I input_repository_pathname  –O output_repository_pathname -V version

-P: RPD password
-I:  Repository path and name
-O: Repository path and new name of the rep you want to name for the downgraded version
-V: To which version you want to downgrade

Steps: 
Go to Cmd and navigate to below path

• C:\Program Files\Oracle Business Intelligence Enterprise Edition Plus Client\oraclebi\orahome\bifoundation\server\bin>

Run below syntax as per you're RPD and RPD version.

• Nqgenoldverrpd -P Admin123 -I D:\RakeshP16.rpd -O D:\RakeshP15.rpd -V 308

After running the syntax you will see below massage.
   Reading D:\RakeshP16.rpd...
   Preprocessing...
   Generating D:\RakeshP15.rpd of version 308...
   Done!!!

Now Try to Open same RPD. You will not get error message.