Microsoft released Windows 10 mobile build 10536 to insiders yesterday night, and while the build is much faster, it does come with a few bugs.
One bug that slipped under the radar of the Windows team was the lack of an SMS messaging app. Some users are reporting that the app does not appear on install, while for others (us included) upon hard resetting the messaging app would no longer be present.
Luckily there is a workaround, you can install any one of the three messaging apps on your device to restore SMS functionality (though we assume only 2 might be of any interest to Windows Insiders)
Download the apps from the source link below (in order of quality) and hold on for our hands on coming shortly after.