No, it is currently an unactivated soft fork known as
BIP 118. I don't think the devs have found a workaround, and are just waiting to see what happens, given that SIGHASH_NOINPUT was not a formal proposal in the past.
Before we can implement eltoo, we need a minor change to Bitcoin: the introduction of the SIGHASH_NOINPUT flag for signatures. This was first discussed a few months ago in the context of watchtowers to help secure Lightning channels, but was not formally proposed. A formal proposal may now be found in the eltoo paper.
