Digital signature outdated or invalid?

[zhangjing-GitHub-Code]

Is digital signature outdated or invalid? When I install it with .ps1, it has an error(?) : 错误: 包或捆绑无数字签名或其签名已损坏。(translate by bing because i'm Chinese: Error: The package or bundle is not digitally signed or its signature is corrupted.) Or because I'm using Windows 7(SP 1)? When I double-clicked it, a window named 证书(certificate?) shows :Valid from 2020/3/17 to 2121/3/18(有效期从 2020/ 3 /17到 2121/ 3/ 18), but It's May now!

[hanskokx]

It is not compatible with windows 7.