The way the configuration is being sync'ed at startup in this Perl Language Sercer seems to be deprecated for quite some time already and might get removed from vscode-languageclient code any time.
To avoid surprises it would be a good time to change from "client notification" (LanguageClientOptions vscode client code) to "server request" using workspace/configuration request and keep it up-to-date with didChangeConfiguration (already implemented).
The way the configuration is being sync'ed at startup in this Perl Language Sercer seems to be deprecated for quite some time already and might get removed from vscode-languageclient code any time.
To avoid surprises it would be a good time to change from "client notification" (LanguageClientOptions vscode client code) to "server request" using
workspace/configurationrequest and keep it up-to-date withdidChangeConfiguration(already implemented).