user103620: Since when lock time exist in Bitcoin transactions? 

user48884: Since the very beginning. Transactions have had the nLockTime field since Bitcoin 0.1.0.

103620: <p>Since when lock time exist in Bitcoin transactions? </p>
 48884: <p>Since the very beginning. Transactions have had the <code>nLockTime</code> field since Bitcoin 0.1.0.</p>
