It should still work, but if you need bottom screen streaming, that has been removed almost five years ago.
If you find a package containing the .cia files, you must install HzMod.cia (the code itself), HzLoad.cia (Home Menu icon), and if you have an old3DS and play games which reboot into Mode 3 (like Smash and Mario Maker 3DS) then you must also install HzLoad_HIMEM.cia as well. You only need regular HzLoad on a new3DS.
The PC-side is a lot more difficult, as there have been numerous versions, so you'll have to try a few methods:
- HorizonScreen-PC 192.168.1.64
- instantly starts streaming (hangs and crashes if 3DS is not reacahble)
- doesn't do anything until you press L (you know you have this version if pressing UP and DOWN causes the JPEG quality number to smear out into an unreadable mess)
- HorizonScreen-PC
- you have to enter the IP in the terminal and it autoconnects (you know it autoconnects because it freezes if 3DS is not available)
- after entering the IP into the terminal, you must press L to connect
- a window pops up but nothing happens, then you have to issue a connect("192.168.1.64") command in the terminal
- you're asked to enter the IP, but pressing L does nothing, then you have to issue a connect() command in the terminal
- SnickerStream
- just use SnickerStream for user-friendly UI, but it doesn't support TARGA frames for games which use 16bit color mode (like Smash and Mario Kart 7)