Srinivas,
CATIA V5 is "
upward compatible" only. If you are running R16, you can open any CATIA file that was saved at R16 level or lower. So you can open both of your parts; R16 and R13.
But, if you are running R13, you can only open any CATIA file that was saved at R13 or lower. You can open your R13 parts, but you'll get an error message when you try to open the R16 parts.
As you were told, it is possible to open the higher level parts, but first you have to "convert" them to the lower level by using the
Downward Compatibility utility program.
Tools + Utility + DownwardCompatibilty is the program,
and it's fairly easy to use. However, the utility strips out the history and only provides a "dumb" solid copy that cannot be editied. So don't replace or delete the R16 part after it's been converted.
I've been told that it's a good idea to run the
CATDUAV5 utility (
DATA Upward Assistant) whenever upgrading to a higher release level.
I've never had a problem with just opening lower level parts and saving them to convert to the higher level, but that's what was suggested to me.
In a perfect world, everyone would use the same release level
