This is the first time I have updated geth.
I was at a build of geth from several weeks ago, and this morning I updated to 1.4.12. I downloaded the pre-built binary to a new location on disk, started it up, then ran geth attach and was surprised that my ether account balance was 0. I then realized that the whole blockchain was re-syncing by running web3.eth.syncing.
I am assuming that when the sync is complete, I will be back to normal, but I am guessing there is a better way to do this? How does one update to a new version of geth without having to go get the whole blockchain again? Or have I misunderstood what is happening?