According to the report from users on Tinhte.Vn, a tech forum in Vietnam, a part of users are now receiving Windows 10 Update, and have ability to download and upgrade to the Windows 10 RTM.
If you are waiting for this upgrade, go to Control Panel > Windows Updates (Windows 7), or PC Settings > Windows Update (Windows 8, 8.1), to check for the update. For all users that have joined Insider program, there is nothing new because Microsoft has confirmed the latest build 10240 (en_windows_10_pro_10240) is the RTM version.
Updated: You can use Command Prompt as an Administrator, and type this command: wuauclt.exe/updatenow to start downloading Windows 10. Make sure Windows Update is enabled and ready to download.
Are you receiving this update like those guys ? I’ve not seen any update yet.