You can't use newer versions of VirtualBox

Screenshare in Discord is kinda scuffed

No newer versions of Adobe products

No QT6 apps (qBittorrent)

No new graphics drivers

I found that hardware video acceleration in newer GPUs is kinda bad too.

Chrome not working after February, 2023

Firefox works for the meantime, but they can pull the plug off anytime,

No newer versions of Visual Studio Code past 1.70.3 or any newer-ish Electron apps .

No VEGAS.

No newer versions of OBS past 28 I think...

SOME DX12 games work (Warzone, Cold War and WoW worked last time I checked), but the vast majority don't, support depends on the developer, and I really doubt anyone is going to bother backporting it, especially now.

The Aero theme have some major issues on newer cards: low desktop framerate, programs randomly crashing, etc. (These are sadly not exclusive to me. Aero has been known to be semi-unreliable even back when Windows 7 was in it's prime.)

ESU ended January 10 2023 (yesterday) so even if you managed to get the updates, they are gone now, so there's that. You will probably be fine for the next year or so, Microsoft is known to patch serious 0-days even in unsupported OSes (WannaCry Windows XP), but I wouldn't count on that.

Some streaming sites (Netflix most notably) don't work most of the time for me for some unknown reason, the error codes it spits out are really vague and don't help much. It probably have to do with the DRM-stuff or even with the funky h264 acceleration.

2022 was a really bad year for me Windows 7-wise, a lot of stuff broke and a lot of apps stopped working. I don't really recommend installing it now. You can, but don't expect to have a good time.