Microsoft this week nudged open the delivery throttle for Windows 10 October 2018 Update, the problem-plagued feature upgrade that the company yanked for more than five weeks this fall before restarting testing with volunteers.

"Windows 10, version 1809, is now fully available for advanced users who manually select 'Check for updates' via Windows Update," read a revised support document.

The October 2018 Update is also known as 1809 in Microsoft's numeric yymm identifying format.

Windows 10 1809 remained unavailable to some systems, even though Microsoft cracked open the upgrade door. According to the support document, four "blockers" - scenarios due to compatibility problems with Intel and AMD display drivers, Trend Micro security software and F5 VPN (virtual private network) software - have yet to be lifted.

By re-opening the "Check for updates" avenue, Microsoft essentially returned to 1809's Oct. 2 status. That was when the Redmond, Wash. company began offering the feature upgrade to so-called "seekers," users brave enough - reckless, some would say - to try just-issued code. Within days, as reports of deleted data swelled, Microsoft withdrew 1809 from general distribution. When it was satisfied that it had fixed several problems, it restarted 1809 on Nov. 13, but with its Windows Insider testers, not the general public.

Monday's move to open 1809 to seekers was the first instance of the upgrade being made available to the latter group.

Microsoft has yet to start offering 1809 to users through its automatic updating services. The company gave no hint on the support document about when that might occur.