When updating bitcoin core do i need to redownload blockchain?

[jackg]

If I were to update bitcoin core (bitcoin-qt) when the next version is released. Will i have to go through the days of redownloading blockchain or will it work with my pre existing installed versions of bitcoin.

If I do have to install it every time then that will get very annoying for bitcoin users that may eventually have to install terabytes of blockchain! (this would be highly unsustainable!)

[achow101]

No. You don't need to redownload the blockchain provided that you did not remove the data directory. When upgrading, the data directory with all of the data including the blockchain and your wallet is not touched. They will still be there and remain the same as they were prior to the upgrade.

[GriffinHeart]

Short answer, as long as you don't MANUALLY delete any files, then just run the new core setup (0.11.0?) and you will only have to download the blocks you missed since you shut down the previous core version. So no, you don't need to redownload the chain.

[unholycactus]

The reason why it would be sustainable as opposed to what you're saying is that as the Blockchain grows in size, the technology (storage, bandwidth) grows too.
When the Blockchain will contain 1TB of blocks, people should be able to store and download it just as fast or even faster than right now.