user10246: I would like to know if timelock transactions are considered standard with the current bitcoin client. If the answer is no, this means that you should use a different client or is it up to user choice?
Furthermore, if someone wants to construct such a transaction which is the structure it should have?

user24925: nLocktime has always been standard and is used to prevent fee sniping. 
OP_CHECKLOCKTIMEVERIFY is currently not implemented and is not enforced. 
A non-standard transaction can be mined by a miner, but will not relay around the normal peer to peer network. A transaction who has a nLockTime which has not been passed is invalid, and won't be relayed or included in a block until this time has passed. 

10246: <p>I would like to know if timelock transactions are considered standard with the current bitcoin client. If the answer is no, this means that you should use a different client or is it up to user choice?
Furthermore, if someone wants to construct such a transaction which is the structure it should have?</p>
 24925: <p><code>nLocktime</code> has always been standard and is used to prevent <a href="https://github.com/bitcoin/bitcoin/pull/2340" rel="nofollow">fee sniping</a>. </p>

<p><code>OP_CHECKLOCKTIMEVERIFY</code> is currently not implemented and is not enforced. </p>

<p>A non-standard transaction can be mined by a miner, but will not relay around the normal peer to peer network. A transaction who has a <code>nLockTime</code> which has not been passed is <em>invalid</em>, and won't be relayed or included in a block until this time has passed. </p>
