Microsoft is serious about quality output. That's why Windows 11 is the highest quality Windows the company has ever released (according to it), and why Azure Sphere OS version 22.01 has been put out to pasture.
Swiss company qiio, which specializes in mobile IoT applications, has received AT&T Network Optimized certification. It covers qiio s »q200 Guardian«, »Concentrator XN« and Development Kit devices, all of which are based on Azure Sphere.