[tz] [IANA #985615] Sudan Time Zone change

[Paul Eggert]

ahmed tajelsir. atyya wrote:
> We would like to inform you that we have changed the time zone of Sudan since 1 November 2017 but we are still facing problem with Google and Microsoft.
> Can you help us to update them?

As Matt Johnson noted, Microsoft fixed this on December 12, 2017, and computers 
that get regular updates for Microsoft Windows should be OK. I expect that users 
will be out of luck if their computer is running an unauthorized version of 
Microsoft Windows, or is running a version so old that Microsoft no longer 
supports it. The current rules for which versions are too old is summarized in 
<https://support.microsoft.com/en-us/help/13853/windows-lifecycle-fact-sheet>.

The situation with Google is more complicated, since Google typically 
distributes Android indirectly via OEMs like Samsung, Huawei, and Xiaomi. Since 
each OEM traditionally has treated their platforms the way Microsoft treats 
Microsoft Windows, each OEM needed to incorporate time zone changes and users 
need to update their phones' system software. This procedure was streamlined in 
Android 8.1 (see 
<https://source.android.com/devices/tech/config/timezone-rules>) so that OEMs 
can push updated time zone information without requiring a system update; 
however, most Android phones run releases older than 8.1 and so must go through 
the older, more-lengthy update process.

There should be a simple workaround for computers or phones that are not updated 
properly: users can set their time zones to Cairo time.