The curious incident of the coins in the night-time.

I sent some coins to an empty wallet using the previous version of the software.
They failed to arrive, although the send was confirmed many times.
Cutting a long story (and many hours of frustration) short...

The destination wallet.dat was created using the previous software, but running in the new software with a fresh download of the blockchain. It was empty before the upgrade.

As a final resort I copied the destination wallet.dat to the machine running the previous software, and placed it in the silk data folder.
When it eventually synchronised the coins appeared. They were still not showing in the same wallet.dat running with the latest version.
So I copied the destination wallet from the machine with the previous version to the machine running the current version.
Having registered with the wallet.dat under the previous version... the coins were now present and correct under the new version.
So I have Two Copies of the same wallet.dat (created with the previous version and containing the same addresses).
One copy was empty when I upgraded to the latest software and refuses to see coins sent to addresses in that wallet.
The other copy was empty until I ran it using the previous software, when it registere receipt of the coins.
The sending wallet was running under the old software.

The coins sent to this wallet.dat will not register under the latest software until they have registered with the software version that created it.

I have not conducted any more tests, but it would seem that the addresses in a wallet created by the previous software need to be initialised by receiving coins under that version before they will function correctly with the new version. The copy that has not been running under the previous version (since the coins were sent) is still reporting that it is empty under the new version.

This could cause compatibility issues with upgrades, so I'm hoping that the team will investigate. Sorry about the longwinded account.