If you are running a very old device that cannot run modern software and you strictly use the VPN for low-risk activities (like unblocking a news website or hiding your IP from your ISP), then Proton VPN 3.4.3 is acceptable if downloaded from a verified source.
Only as a last resort.
If possible, install a lightweight Linux distro (like Xubuntu or Linux Mint Xfce) on your old PC. Then install the latest flatpak version of Proton VPN. Linux versions are far lighter than Windows equivalents. descargar proton vpn 3.4 3