Thank you.  I understand that not all bitcoin clients have to download the blockchain to operate however, something I'm not clear on is whether or not those clients properly sync up a wallet.dat. As I understand it, if I store away a wallet.dat in a vault and then pull it out six months later, it needs to see all the new blockchain transactions to be caught up, and I'm concerned that software that does not download the full blockchain will not provide the necessary transactions to the wallet.dat.  I hope that makes sense.