A new update is rolling out to Windows Insider devices running Windows 10 Mobile Build 10166 (that’s the build I have on all my devices). Before you get too excited it is not the Build 10240 that has been hinted to be the next preview build. The update identifies itself as “Developer Enhancements” update.
You may need to enroll to “Insider Fast” again by opening Windows Insider app that has been updated some days ago. If you don’t have Windows Insider app on your devices anymore you need to reinstall and then go for Insider Fast. The changelog is unknown and we didn’t notice any change in even the developer options.
Thanks Sami & others for sending this tip. Cheers!!