Knowledgebase : Auxiliary Software > IDF Editor
If the older version is from the previous release, then yes. Use the pull-down File menu and select Transition. This will update the older file to the newer version.

If the older version is older than the previous release, then you must use the multiple transition program. You can download the transition programs from this site.

(That is http://energyplus.helpserve.com and go to the downloads area).

The Multiple Transition folder is set up on the EnergyPlus install.
Unzip the file into the MultipleTransition folder and use the IDF Converter GUI program to transition your older files.