The "portable" nature of v3.9.8.6356 is its primary strength. In data recovery scenarios, installing software onto a drive containing lost files is a common mistake that can permanently overwrite the very data a user intends to recover.
This specific build number (3.9.8.6356) was never officially released as a free portable tool by GetData. Almost every copy of this version circulating online is a cracked, repacked, or "loader" version designed to bypass the $70-$100 license fee. GetData Recover My Files v3.9.8.6356 Portable