No mention was made of Windows 10 Mobile by Belfiore, leading to speculation that the platform is dead.
Belfiore tweeted: "iPhone-carrying Windows Insiders... Come and get it!", referring to the app.
In response, a user going by the handle J R Dub, tweeted: "if you use an iPhone, quit Microsoft. I'm forced out of a Windows phone, you continually feed the competitors."
iPhone-carrying Windows Insiders... Come and get it! https://t.co/5kSSeNxM6d— Joe Belfiore (@joebelfiore) July 28, 2017
But this did not mollify Windows Phone fans, with a tweet from one George Ponder saying: "Hey Joe! Why promoting iPhones so much lately? Have you forgotten Windows Phones or are the rumours true that they are dead?"
And he tweeted again: "Surely I'm not the lone holdout still hoping in miracles. That somebody at MSFT comes to their senses and breathes life back into WinPhones."
Another Windows Phone enthusiast, going by the handle seabreem, wrote: "Shame on Windows 10 Mobile, shame on Microsoft's iPhone fan-employees, shame on LinkedIn web wrapper, shame on current Lumia950/XL users."
Referring to the app that Belfiore had tweeted about, another Twitter user Gustavo Fontana tweeted: "This is a cheesy hack Joe, not useful. What makes sense is shipping an Edge browser app for iPhone. Then also keep Web passwords in-sync."
In Microsoft's latest results, for the fourth quarter of the financial year, revenue for the phone division was seen to be going backwards, with the statement: "Phone revenue was immaterial and declined US$361 million."