After last weeks fork the bitcoin development team are taking proactive steps to ensure that the problem will not happen again while still being able to push forward with the 0.8 series of updates and upgrades to the bitcoin system and network and have released their official plan.

What's the plan?

The plan is a simple one, a new version called 0.8.1 of the official reference client will be released tomorrow that has all of the improvements of the 0.8 line with the important addition of a routine that will check to make sure that any block created is compatible with previous clients temporary preventing any forks similar to the one we saw last week.

When 0.8.1 is released tomorrow it is recommended that everyone including the miners upgrade as soon as possible.

At the same time messages will be sent through the bitcoin network to all users running pre 0.8 clients asking them to upgrade to 0.8.1 by the 15th of May 2013 referring them to a page on the official bitcoin webpage (the page has already been created, you can see it at http://bitcoin.org/may15.html).

Additional messages will also be sent out on the 15th of April and 8th of May if you still have not upgraded once again asking the user to upgrade to 0.8.1 as soon as possible.

Finally on the 15th of May the routine that checks that new blocks are backwards compatible with pre 0.8 versions of the client will be disabled allowing blocks to be created up to a size of 1 MB at the discretion of the miners.

What do I do?

If you are running a full bitcoind client for whatever reason when the new binary become available tomorrow at http://bitcoin.org/ download, install them and then forget about it, your job is done.

What happens if I don't upgrade?

This is one of my favourite things about bitcoin, if you disagree with the changes (for whatever reasons) you are free to continue running pre 0.8 clients.

There is a caveat to that though, the bitcoin network runs on a consensus, by running a version of bitcoind of a different version with different rules to block creation you are voting to keep the older rules for block creation. If enough people and miners share your opinion that the old block rules are better sometime after the 15th of May a new hard fork will be created and we will have two valid blockchains, one that the 0.8 people follow and one that the pre 0.8 people will follow.

It is most likely at this moment though the concencus seems to be to upgrade and the pre 0.8 chain will never come into existence, so if you don't upgrade it is unlikely that you will be able to use the bitcoin network until you do.

I have included below the announcement on the Bitcoin-Development list.