Microsoft today resumed delivery of Windows 10 previews to its Insider program participants after taking a four-week break.
The new preview, designated build 11099, was offered to beta testers who have selected the "Fast" ring, or delivery track.
As with its predecessor -- which appeared Dec. 16 -- build 11099 has no major new features or visible changes. "Our focus through the holidays was on structural improvements to OneCore, which is the shared core of Windows across devices," wrote Gabriel Aul, engineering general manager for Microsoft's operating systems group, in a post to a company blog Wednesday.
OneCore is Microsoft's label for the single kernel -- along with associated dynamic link libraries (DLLs) and other bits of the OS -- that Microsoft uses as the foundation of Windows 10 across multiple platforms, ranging from PCs and tablets to smartphones, the Xbox console, Internet-of-things (IoT) devices and even the pending, futuristic Hololens.
Aul said noticeable changes won't appear for a few more builds as engineers continued to optimize the OneCore code, a task the company has been working on for the last two months.
Last month, Aul promised that previews would appear on a faster tempo -- at the same time warning participants to expect more bugs than in the past -- and he repeated the pledge and caveat today. "[The faster pace] also means that the builds we release to the Fast ring may include more bugs and other issues that could be slightly more painful for some people to live with," Aul said.
The 28 days since the last build was a significantly shorter stretch than the end-of-the-year break the Insider program took in 2014. Then, Microsoft issued its final preview on Oct. 31 and didn't resume delivery until Jan. 23, 2015, an 84-day interval.
Among the known problems in build 11099, Microsoft called out one that that remained from the previous preview: Windows 10 will again reset default file type associations, which will affect anyone who changed the original settings to, say, launch a different player app when opening a video or audio file. Another known issue may crash applications that rely on Adobe's Flash. Microsoft's own Internet Explorer 11 (IE11) and Edge browsers, however, were not affected by that bug.