I thought that HTLCs was just a kind of a script construct that would allow to unlock funds for a period of time, which can be unlocked to anyone that provides the original string that matches the hash. Does it need new OPCODEs that are not working in bitcoin yet?

I ask this because I can see the BIP where this is proposed, linked from here: https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2016-July/012894.html . However, neither the pull request nor the BIP inclusion seem to have had any activity.

Does this BIP need a soft-fork that hasn't been implemented/deployed yet?