While the rollout of Windows 10 version 1809 (the October 2018 Update) has been problematic, Microsoft really does try to avoid sending the update to configurations that it knows just won't work properly.

One of these situations involved PCs with Apple's iCloud client. The system would break when trying to sync or update Shared Albums when used on Windows 1809, and, accordingly, Microsoft blocked installation of the update on systems with iCloud installed. Similarly, the iCloud client could be installed on Windows 1809 because Apple had a broken version check that didn't recognize that version 1809 was indeed the current Windows version.

Both issues appear to be fixed now. Apple has released iCloud for Windows version 7.8.1, which resolves both the crash and the bad version check. After upgrading to this version, the Windows 10 Update will no longer be blocked and will install in the normal way.

Several other upgrade blocks remain in place. Intel apparently inadvertently sent some display drivers to OEMs that used or enabled some unspecified unsupported feature of Windows; these block installation of the update. The presence of the F5 VPN client is also blocking, as certain VPN configurations cause a loss of network connectivity. Certain Trend Micro software is known to be incompatible and is waiting on a patch from Trend Micro.

Finally, there's one blocking issue that may very well not get fixed. Old Radeon video cards using the HD2000 and HD4000 GPUs are no longer supported by AMD. Using the latest AMD drivers with these cards results in occasional blue-screen system crashes along with other, more benign crashes. Accordingly, Microsoft isn't shipping the update to anyone with an HD2000 or HD4000 card.

If this block remains in place, systems with those cards will soon cease to receive security updates. First hitting the market in 2007 and 2008, these cards are certainly long in the tooth, but they're probably serviceable enough for regular desktop Windows usage.

This isn't the first time that a GPU driver issue has been a sticking point. Windows 10 version 1703 was blocked for systems using Intel's Clover Trail processor because of an incompatibility issue with the GPU driver. As such, they were stuck on version 1607. In that case, however, Microsoft had already committed to long-term security support for version 1607, so while the systems were unable to get the very newest Windows release, they won't be opened up to any particular security risk.

However, that's not the case this time around, as version 1803 isn't going to receive long-term support. It's not clear how this particular issue is going to be resolved.