Let's make January 14 2018 Bitcoin Cash Change the Address Day!
The new base32 cashaddr address change is optional. It isn't a hard fork protocol upgrade. However, it is still tremendously important that as many as possible participants in the Bitcoin Cash ecosystem join together to switch on the same day. This will provide the smoothest transition for all users, businesses and all newbies.

ABC Bitcoin's lead developer Amaury Sechét initially proposed deploying the base32 cashaddr format on January 14 2018. Bitcoin Unlimited members overwhelmingly voted this month to support the format. Electron Cash has also announced support. Bitpay has said they're on board as well.
There are a lot of benefits to the new address format. Lots of users mistakenly send BTC coins to a BCH address and vice versa. It's not the end of the world, but it often necessitates a lot of extra work to recover coins.
In addition Sechét writes:
  • "It uses a very strong checksum which ensure detection of up to 6 errors in an address and 8 in ‘burst’. Larger number of errors have one chance over a thousand billion to lead to a valid address.
  • It encodes more compactly in QR codes as it allows the use of the alphanumeric mode.
  • It is much faster to encode and decode than the previous format, which is important for system having to handle a large number of addresses."

If there is confusion and some exchanges/wallets/payment processors switch and others don't:
  • New users will be very confused. Already using crypto addresses and QR codes is really confusing to new users. If there are two kinds of addresses that look totally separate it just adds to the things newbies have to wrap their heads around before jumping in.
  • New businesses entering the space will be put off. It will be another decision they have to make. Which address format to support or how many different kinds of addresses to support. They'll also have to set apart resources to deal with tickets from customers confused about the different addresses.
  • Existing users will also be extremely inconvenienced. If one wallet supports base32 cashaddr format and one only supports the traditional format simple transactions quickly become a headache.
Bitcoin Cash should be the best money for everyone. Paying with Bitcoin Cash should be hassle-free. The only way we can do that is if we have a smooth upgrade ecosystem-wide.

So what does the new format look like?
According to the specs:
The address is composed of
  1. A prefix indicating the network on which this address is valid.
  2. A separator, always :
  3. A base32 encoded payload indicating the destination of the address and containing a checksum.
In addition: Bitcoin Cash's network prefix is bitcoincash
This means:
If the legacy address is 1BpEi6DfDAUFd7GtittLSdBeYJvcoaVggu, the new cash address will look like bitcoincash:qpm2qsznhks23z7629mms6s4cwef74vcwvy22gdx6a.

But what about old bitcoin in old addresses?
The upgrade won't effect any old bitcoin in old addresses. There is no need to move Bitcoin Cash to new addresses, as the upgrade is in the format only. A good way of thinking of it is like dates. January 14th 2018 or writing it in shorthand — 1/14/2018 (American style). Both point to the same day; but the way they are formatted looks quite different. No Bitcoin Cash coins will be lost or made unusable, and wallets should support toggling in the advanced settings if the user needs to use the traditional address.

The new address format was proposed over two months ago. Now less than a month remains to prepare the rollout. Let's make the switch to cashaddr addresses a day other cryptocurrencies are envious of because it is so smooth and so hitch-free.


~Bitcoin Cash Ecosystem Updates~

  spent 20.0¢
Thanks for the each to understand summary.
If QR codes can only do upper case in alphanumeric mode, what about "bitcoincash:"?
   3yr ago
  spent 20.0¢
This seems interesting. While I do think it's fun to send BCH to BTC addresses, the second time it starts to get old when accidentally mixing the two. It could be helpful to display "bitcoincash:" as a prefix. On the other hand, I kinda want BTC to change their address in order to keep orthodoxy
   3yr ago
  spent 20.0¢
@Jeffery, It'll take three years before that other team could roll out a change like this.
   3yr ago