Along with the announcement of 'Windows 10 Insider Preview Build 16176', Microsoft officially announced that only a set of few Windows 10 Mobile devices will get the Creators Update and future insiders build.
If you are already in latest insider preview build on old devices, you won't get the feature update but will receive cumulative updates.
Here is the list of mobile devices that will get Windows 10 Creators Update and continue receiving Windows 10 Mobile Insiders Preview builds:
- HP Elite x3
- Microsoft Lumia 550
- Microsoft Lumia 640/640XL
- Microsoft Lumia 650
- Microsoft Lumia 950/950 XL
- Alcatel IDOL 4S
- Alcatel OneTouch Fierce XL
- SoftBank 503LV
- VAIO Phone Biz
- MouseComputer MADOSMA Q601
- Trinity NuAns NEO
If you have any mobile device that's not in the above list, will not officially receive the Windows 10 Creators Update. Dona Sarkar, in her official blog post, mentioned it clearly:
Devices not on this list will not officially receive the Windows 10 Creators Update nor will they receive any future builds from our Development Branch that we release as part of the Windows Insider Program. However, Windows Insiders who have devices not on this list can still keep these devices on the Windows 10 Creators Update at their own risk knowing that it’s unsupported.
This was well expected, because Creators Update was not performing well on older devices where Windows Insiders were running them. In case you want to check what's new in 'Windows 10 Insider Preview Build 16176', check out the official blog post for details.