We have to delete 2.15 to install the new version?
Yes, just delete the fh2 mod folder from your "C:\...\EA GAMES\Battlefield 2\mods" or wherever your main BF2 folder is located and the fh2 folder from your Battlefield 2 folder in your "My Documents"
Then just install FH2.2 and be happy!
*EDIT* but watch for the information Lightning will post just in case I got it wrong! :p