If Bitcoin hard forks, do alternative clients need to be updated?

[Mt. Gox]

Currently there is some discussion about hard forking Bitcoin so that the maximum block size is increased. That would require a mandatory update for Bitcoin Core. But what about alternative clients like Electrum and Multibit? Do these also need to be updated or not? Since they rely on external servers, is it just these servers that need to be updated or everyone who uses the program?

[jdebunt]

Currently there is some discussion about hard forking Bitcoin so that the maximum block size is increased. That would require a mandatory update for Bitcoin Core. But what about alternative clients like Electrum and Multibit? Do these also need to be updated or not? Since they rely on external servers, is it just these servers that need to be updated or everyone who uses the program?

Depends on whether or not they pull data from an API somewhere or have full clients running themselves.

In most cases, it's just their end that needs an update. Yet they could release a mandatory mobile client update as well...

[jim618]

For a hard fork the devil is in the details.

For instance with MultiBit a pure change to the size of the blocks shouldn't make any difference, as we bloom filter the blocks to just grab the transactions we are interested in. We talk directly to the Bitcoin Core nodes.

As hard forks are so rare, I imagine there will be a set of fixes and tweaks added to the protocol at the same time. Any of these may require changes to (in our case) the bitcoinj library and hence an update.


I imagine there will be a testnet set up that we can test out the changes and make sure nothing breaks.

[ThomasV]

Electrum clients will not be affected by an increase in the block size

[virtualx]

Currently there is some discussion about hard forking Bitcoin so that the maximum block size is increased. That would require a mandatory update for Bitcoin Core. But what about alternative clients like Electrum and Multibit? Do these also need to be updated or not? Since they rely on external servers, is it just these servers that need to be updated or everyone who uses the program?

Only if the majority of the miners agree there can be a protocol update. Electrum and Multibit have active development. A block size increase probably has effect on the source code.

[Mt. Gox]

Thanks for the answers. That was similar to what I thought (since the external servers grab their data from core nodes which are full clients).

Currently there is some discussion about hard forking Bitcoin so that the maximum block size is increased. That would require a mandatory update for Bitcoin Core. But what about alternative clients like Electrum and Multibit? Do these also need to be updated or not? Since they rely on external servers, is it just these servers that need to be updated or everyone who uses the program?

Only if the majority of the miners agree there can be a protocol update. Electrum and Multibit have active development. A block size increase probably has effect on the source code.

If a protocol update was announced and not all miners agreed to the fork then the network would bifurcate. Electrum and Multibit have rapid development as you point out so I would think that if there is any compatibility issue (and there seems to be none for the example that I posted in the OP) then they would modify their code to "speak" with the core nodes on the correct fork of the Bitcoin blockchain.

At least that was my assumption.

[redsn0w]

Thanks for the answers. That was similar to what I thought (since the external servers grab their data from core nodes which are full clients).

Currently there is some discussion about hard forking Bitcoin so that the maximum block size is increased. That would require a mandatory update for Bitcoin Core. But what about alternative clients like Electrum and Multibit? Do these also need to be updated or not? Since they rely on external servers, is it just these servers that need to be updated or everyone who uses the program?

Only if the majority of the miners agree there can be a protocol update. Electrum and Multibit have active development. A block size increase probably has effect on the source code.

If a protocol update was announced and not all miners agreed to the fork then the network would bifurcate. Electrum and Multibit have rapid development as you point out so I would think that if there is any compatibility issue (and there seems to be none for the example that I posted in the OP) then they would modify their code to "speak" with the core nodes on the correct fork of the Bitcoin blockchain.

At least that was my assumption.

Hmm it could be possible, if it will be an hard fork I think it cannot exist two or more "blockchain" at the same time. So it will be a really 'discomfort' to all the users that "are not user friendly" with bitcoin. However if it can be possible 2 fork of the chain at the same time, what it will happen if I'll send 1 btc from the FORK-A to your address (bitcoin core updated) in the FORK-B?