After a sufficient number of nodes upgrade on the network, the LN protocol may be updated to drop the “update_fee” message, which has been a source of unnecessary force closes during fee spikes for years now. With removal of this protocol message, commitment transactions could be set to a static 1 sat/vbyte feerate. With TRUC transactions, we can ensure that competing commitment transactions with anchor spends are allowed to RBF each other over the network, and if there are competing output spends from the same commitment transaction, that RBF can occur no matter which output is being spent. TRUC transactions are also allowed to be 0-fee, allowing reduction in spec complexity. With TRUC’s sibling eviction, we can also drop the 1 block CSV locktimes, since we are no longer overly concerned with what unconfirmed outputs are being spent, as long as each party can spend a single output themselves