An ‘extended’ UTXO solution would need the inclusion of two features that the current UTXO model lacks:
1.To be able to keep the contract in its current state.
2.To be able to ensure that the same contract code is used throughout the transaction sequence.
Cardano’s $ADA ledger architecture extends on the UTXO model to accommodate multi-assets and smart contracts while maintaining the UTXO model’s benefits, transaction’s success or failure is solely determined by the transaction and its inputs

分為4種UTXO
1. Classic UTXO
$BTC, $BCH, $BSV, $LTC, $DOG, $DASH

2. EUTXO支援複雜的智能合約與去中心化應用
ADA, $ERG (Ergo)

3. 隱私UTXO
利用 UTXO 的離散特性，結合環狀簽名、零知識證明或保密交易來隱藏交易金額與地址資訊
$XMR (Monero), $ZEC (Zcash)

4. 混合型公鏈UTXO: 結合 DAG或多線程並行技術
$KAS, $QTUM , $CKB
不舉拿種UTXO?