Use hugo.IsServer instead.
I can see in your git that you appear to have changed this to avoid the error, but when I try to use this theme, I still get the error:
.Site.IsServer was deprecated in Hugo v0.120.0 and will be removed in Hugo 0.135.0. Use hugo.IsServer instead.
I have tried cloning and using this as a submodule. I get the same error. I am not sure if I am doing something wrong, or if there is some other error. I cannot locate any place where .Site.IsServer is still being used in your repo, but I still get this error nonetheless.
rel: #180 bowman2001/hugo-mod-image/pull/13 bowman2001/hugo-mod-image/pull/14 (same as 13 there)
@ProfLear the site.IsServer is still in the latest release. The commit that solves that issues is not yet published as a new version so whenerver go gets the module, it gets the module the code before the latest commit. I create a new issue : https://github.com/bowman2001/perplex/issues/183