Layer 2 developer StarkWare has used its new STARK validator and OP_CAT technology in the Bitcoin testing environment Signet network, OP_CAT a proposed upgrade to Bitcoin that aims to bring Ethereum-style "smart contract" programmability. While OP_CAT has no shortage of supporters, it is still in the early stages of gaining the consensus needed to integrate into Bitcoin's core software. "StarkWare publicly supports the approval of this proposal as it will bring clear benefits to the Bitcoin community and the broader blockchain ecosystem," the company said in a press release.