There appear to be no breaking protocol changes to the core logon sequence, as usual.
It appears that a new status code has been added to SID_AUTH_ACCOUNTLOGONPROOF: 0x0000000E. This is actually a success code, except that it also implies that the client should request that the user register an e-mail address with the current account.
This is not fully a breaking change; logging on to the account ahead of time with the official client (and registering an e-mail or declining to do so) should mitigate the problem.
Please note that this is not an issue with BNLS and cannot be resolved by changes to BNLS.
The BNLS Protocol Spec (http://www.valhallalegends.com/yoni/BNLSProtocolSpec.txt) has been updated to document this new status code.
No changes were made to BNLS.