If you've installed Windows 10 Build 10240, it's possible that you're running near-RTM code. It has been suggested that it is in fact final code, but a new update from Microsoft proves otherwise.
This is not a new build so soon after the other, but a regular, run-of-the-mill update. That’s not to say it's not important -- it is a bug-fixing update which addresses some last minute issues. KB3074665 is listed as a security update, and Microsoft's Gab Aul also describes it as "a package of fixes based on reported issues in 10240".
As we know, Microsoft is forcing updates on Windows 10 users, but you don't have to wait for it to be pushed to your computer. Forced updates can take a little while to propagate, so you can fire up Windows Update in Settings to perform a manual check if you like. The latest patch was announced by Aul on Twitter:
We're releasing an update package on WU for PC build 10240 today. It will install automatically or you can check for updates to grab it.
— Gabriel Aul (@GabeAul) July 17, 2015
A lot of Windows 10 users reported issues with the update failing to complete installation, or taking a very long time to finish installing, but this could be a case of teething problems. The update -- which is "cumulative and includes the last package's security fix" -- is one of the last to be released before the big launch in just a few days' time.