I just came across this article on feature updates for their compiler during the VS2017 lifetime, I thought the section talking about version numbers might be of interest to the boost build maintainers and boost config maintainers.
The interesting part about version numbers is three-quarters of the way down the post, under the "MSVC toolset version number increases to 14.12".
The table that they have there is also illuminating:
Visual Studio Version | MSVC Toolset Version | _MSC_VER
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VS2015 and updates 1, 2, & 3 | v140 in VS; version 14.00 | 1900
VS2017, Version 15.1 & 15.2 | v141 in VS; version 14.10 | 1910
VS2017, Version 15.3 & 15.4 | v141 in VS; version 14.11 | 1911
VS2017, Version 15.5 | v141 in VS; version 14.12 | 1912
---------------------------------------------------------------
Just wanted to give people a heads-up that this is something that may be encountered in the wild soon.
Tom