Replaced? KB4012598 is the latest update for XP SP3 x86
Maybe you have not understood that this update (May12th) applies to windows xp
NO embedded
For embedded , the patch (KB4012598) was applied March 14th , like said at the beginning of your link
In March, we released a security update which addresses the vulnerability that these attacks are exploiting. Those who have Windows Update enabled are protected against attacks on this vulnerability. For those organizations who have not yet applied the security update, we suggest you immediately deploy Microsoft Security Bulletin MS17-010.
Then , May9th (3 days before the release of the patch for xp no embedded) , as I said (as MS said) KB4018466
Supersedes KB4012598 just fot WS 2008 and WXP Embedded
"Update 5/22/2017: Today, we released an update to the Microsoft Malicious Software Removal Tool (MSRT) to detect and remove WannaCrypt malware.For customers that run Windows Update, the tool will detect and remove WannaCrypt and other prevalent malware infections.
Furthermore , do not confuse the patch to close the flaw (KB4012598 May12th).... and detection + treatment of malware when it passed the flaw (MSRT KB890830 May22th) , more or less antimalware.