Microsoft ended support for Windows XP on April 8th, 2014, an OS initially released in 2001. This means that not even critical security updates will be released anymore. Without security updates, using a bitcoin wallet on a XP machine is irresponsible at least.
In addition to that, with 0.12.x there have been varied reports of Bitcoin Core randomly crashing on Windows XP. It is not clear what the source of these crashes is, but it is likely that upstream libraries such as Qt are no longer being tested on XP.
We do not have time nor resources to provide support for an OS that is end-of-life. From 0.13.0 on, Windows XP is no longer supported. Users are suggested to upgrade to a newer version of Windows, or install an alternative OS that is supported.
No attempt is made to prevent installing or running the software on Windows XP, you can still do so at your own risk, but do not expect it to work: do not report issues about Windows XP to the issue tracker.
From 0.13.1 onwards OS X 10.7 is no longer supported. 0.13.0 was intended to work on 10.7+, but severe issues with the libc++ version on 10.7.x keep it from running reliably. 0.13.1 now requires 10.8+, and will communicate that to 10.7 users, rather than crashing unexpectedly.
When a newly created transaction failed to enter the mempool due to the limits on chains of unconfirmed transactions the sending RPC calls would return an error. The transaction would still be queued in the wallet and, once some of the parent transactions were confirmed, broadcast after the software was restarted.
This behavior has been changed to return success and to reattempt mempool insertion at the same time transaction rebroadcast is attempted, avoiding a need for a restart.
Transactions in the wallet which cannot be accepted into the mempool can be abandoned with the previously existing abandontransaction RPC (or in the GUI via a context menu on the transaction).
bitcoin-0.13.2-aarch64-linux-gnu.tar.gz 03-Jan-2017 08:04 9505843 bitcoin-0.13.2-arm-linux-gnueabihf.tar.gz 03-Jan-2017 08:04 8842928 bitcoin-0.13.2-i686-pc-linux-gnu.tar.gz 03-Jan-2017 08:05 24320334 bitcoin-0.13.2-osx.dmg 03-Jan-2017 08:05 13606103 bitcoin-0.13.2-osx64.tar.gz 03-Jan-2017 08:05 18940662 bitcoin-0.13.2-win32-setup.exe 03-Jan-2017 08:05 12590672 bitcoin-0.13.2-win32.zip 03-Jan-2017 08:05 22480628 bitcoin-0.13.2-win64-setup.exe 03-Jan-2017 08:06 13144152 bitcoin-0.13.2-win64.zip 03-Jan-2017 08:06 23832542 bitcoin-0.13.2-x86_64-linux-gnu.tar.gz 03-Jan-2017 08:06 23916428 bitcoin-0.13.2.tar.gz 03-Jan-2017 08:06 5303321 bitcoin-0.13.2.torrent 03-Jan-2017 08:10 14605