Ahh gotcha, of-course, sorry.
Yes, correctly understood
Indeed, msvc 14 is msvc 2015, which I used at one point in time, and as you say 14.20 is msvc 2019, your specific version actually is 14.26, but 14.20 should work, or maybe 14.2 if doesn't, as guessing then means all msvc 2019, though no expert whatsoever in these matters lol. Note, if you change it in the patch in the place where I changed 14 to 14.00, then that is ignored, because doesn't get used at all when using py3.8, and so 'msvc' is used for that python version, which I didn't change as worked fine for msvc 2019, and just is problematic for msvc-2017(14.1 e.g. 14.16 when I used it), but you can precise it more if wanted of-course and sorry in advance if you already was talking about changing it there on the b2 line directly or after my old unused 14.00 change and where states just msvc, before the b2 line.
Btw, forgot a previous edit previous too; you can delete gtk-cache if wanted, but then it will have to download all gtk3 related packages and reclone git repo's instead of pull for updates, so saves time and hence, I kept it and only removed it when/if running uninstall_components.cmd.
It's same boost in lt1.2.3, and I just remade it, though in my usual lazy way, so you will need fixup with your wanted changes afterwards like before.
http://s000.tinyupload.com/index.php?fi ... 2644845975 (goes in libtorrent-build with the others and it just moves built libtorrent.pyd into single needed place i.e. libtorrent\lt1.2.3\Lib\site-packages, for when user selects lt1.2.3 in installer during install - fully tested working of-course, twice actually, as needed NUL out an extra RD command, as python dir was removed here by uninstaller and just kept for making sure not changing later, though again, bloody ineffecient to do it like this and not keeping python always when not updated, and just using venv's in buildscripts, but as said, lazy
) Crap, Just remembered I forgot remove the last pause command, which I only use during testing and remove afterwards, but I think you use that yourself anyway, but otherwise, please delete yourself, thanks.
Btw, up to you, but myself I would only rebuild lt1.2.3 when going from bigger py-upgrade i.e. next when going to 3.9. Why I say that, is because in the beginning I just installed and used the libtorrent.pyd that Cas built and uploaded to pypi, so installed from pip, like deluge itself, called deluge-libtorrent or something of the sort, but later rebuilt it myself as it wasen't built with crypto=openssl, and so didn't support https trackers and showed tracker error upon them as I got reported. Anyway, when installing that libtorrent.pyd with pip, which was from a wheel package, then it had a fixed python version in name and install-file so could only be installed if using py3.6.x, but not e.g. 3.5 or 3.7 etc, so kinda though that it then must have been okay to only rebuild when bigger updates to python came. Maybe it even works also in bigger py updates when building yourself, dunno, probably if not broke compatibility with bigger API changes, but anyway, since python bigger updates only happens rarely, then for me was fine to just redo upon those. but of-course up to you if wanna rebuild more often then that i.e. upon every point update of python.
The user-config.jam, or whatnot, I know is referenced in official libtorrent building guide among others, probably also on deluge main site in it's building guide, though pretty outdated I presume, but still, if wanna try mess with that, and possibly lt1.1.x also works now with a newer or even newest boost, who knows, though as said, didn't change anything with me(that extra user-config.jam file or whatever), and needing patch setup.py anyway, but as also said, not tested this boost situation in long time, i.e since boost 1.71 was newest and latest libtorrent was I believe 1.2 or 1.2.1 and older other branch 1.1.11 I believe. Last, I don't use b2 option encryption=on because is default anyways just so don't think I forgot, as e.g. is used in that deluge building guide underneath here.
https://www.libtorrent.org/building.html
https://dev.deluge-torrent.org/wiki/Building/libtorrent
Sorry for "intruding", carry on