--- modules/puppetca/puppetca_main.rb    2020-01-16 08:41:51.557765000 +0100
+++ modules/puppetca/puppetca_main.rb    2020-01-16 14:08:29.559916000 +0100
@@ -66,7 +66,11 @@
     # list of all certificates and their state/fingerprint
     def list
       find_puppetca
-      command = "#{@sudo} #{@puppetca} --list --all"
+      if @puppetca.include?("puppetserver")
+        command = "#{@sudo} #{@puppetca} list --all"
+      else
+        command = "#{@sudo} #{@puppetca} --list --all"
+      end
       logger.debug "Executing #{command}"
       response = `#{command}`
       unless $? == 0
@@ -99,18 +103,30 @@
       end

       default_path = ["/opt/puppet/bin", "/opt/puppet/sbin", "/opt/puppetlabs/bin"]
-      @puppetca = which("puppetca", default_path) || which("puppet", default_path)
+      puppet = which("puppetca", default_path) || which("puppet", default_path)
+      puppetserver = which("puppetserver", default_path)
+      puppetserver_version = `#{puppetserver} --version`.split(": ")[1]

+      if puppetserver_version >= "6"
+        @puppetca = puppetserver
+      else
+        @puppetca = puppet
+      end
+
       unless File.exist?(@puppetca.to_s)
         logger.warn "unable to find puppetca binary"
         raise "unable to find puppetca"
       end
       # Append cert to the puppet command if we are not using the old puppetca command
       logger.debug "Found puppetca at #{@puppetca}"
-      @puppetca << " cert" unless @puppetca.include?("puppetca")
+      if @puppetca.include?("puppetserver")
+        @puppetca << " ca"
+      else
+        @puppetca << " cert" unless @puppetca.include?("puppetca")
+      end

       # Tell puppetca to use the ssl dir that Foreman has been told to use
-      @puppetca << " --ssldir #{ssl_dir}"
+      @puppetca << " --ssldir #{ssl_dir}" unless @puppetca.include?("puppetserver")

       if to_bool(::Proxy::PuppetCa::Plugin.settings.puppetca_use_sudo, true)
         @sudo = ::Proxy::PuppetCa::Plugin.settings.sudo_command || which("sudo")
@@ -137,7 +153,7 @@
       "#{puppetdir}/autosign.conf"
     end

-    # parse the puppetca --list output
+    # parse the puppetca list output
     def certificate str
       case str
         when /(\+|\-)\s+["]{0,1}(.*\w)["]{0,1}\s+\((\S+)\)/