Quote from: ChuckBuck on Today at 03:02:58 AM

I understand what you explained, it's really good. But is he not the only one who can see the transaction? As soon as he uses the new client, his transaction is still there, he can manage to cancel it. The transaction is still there but not done, right? I mean people who can see transaction? Only him?

It will be seen on your client, not in explorer anymore since the tx may be not standard or rejected by mempool.

Quote from: ChuckBuck on Today at 03:02:58 AM

I would also like to ask, how do I cancel a BTC transaction if it's not done after 14 days?

I don't know if it's possible in other wallet, it can be done im Electrum wallet. In electrum, if you click the tx, there will be option to remove the tx.