Oh, but did I dream or the walled briefly said it wanted an update? I'm running v0.5.0.0-g0-beta (64-bit) . I went out to check a newer version and now the message has disappeared. MD5 of my install file is 87b1557e2d4cbf8c95616b48c34ff537 (as well as the latest I could find linked in the homepage)
Ok maybe it's my brain that can't sustain all that heat! :-D
I'm now seeing this issue where the Wallet 0.5.0 warns you about having an obsolete version. I'm debugging it now.
Edit: The warning can be safely ignored. I'll build a new Wallet 0.5.1 to fix this issue and also add a checkpoint for block 50,000 to seal the network transition to algo version 2.