diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8c50b16..1b6e7af 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # CHANGELOG
 
+## 0.2.12
+
+* Added flag for systemd release: **eyp_systemd_release**
+* Added support for **UnsetEnvironment** to **systemd::service** and **systemd::service::dropin** - fixes [issue 152](https://github.com/NTTCom-MS/eyp-systemd/issues/152)
+
 ## 0.2.11
 
 * Added **capability_bounding_set** to **systemd::service** and **systemd::service::dropin**
diff --git a/lib/facter/eyp_systemd_release.rb b/lib/facter/eyp_systemd_release.rb
new file mode 100644
index 0000000..8986dd1
--- /dev/null
+++ b/lib/facter/eyp_systemd_release.rb
@@ -0,0 +1,15 @@
+require 'puppet'
+
+if File.exist?('/bin/systemctl')
+
+  systemd_release=Facter::Util::Resolution.exec('bash -c \'/bin/systemctl --version 2>/dev/null | head -n1 | awk "{ print \\$NF }" \'')
+
+  unless systemd_release.nil? or systemd_release.empty? or !/\A\d+\z/.match(systemd_release)
+    Facter.add('eyp_systemd_release') do
+      setcode do
+        systemd_release
+      end
+    end
+  end
+
+end
diff --git a/manifests/service.pp b/manifests/service.pp
index 4e26495..a72575d 100644
--- a/manifests/service.pp
+++ b/manifests/service.pp
@@ -17,6 +17,7 @@
                           $remain_after_exit           = undef,
                           $type                        = undef,
                           $env_vars                    = [],
+                          $unset_env_vars              = [],
                           $environment_files           = [],
                           $permissions_start_only      = false,
                           $timeoutstartsec             = undef,
@@ -86,6 +87,20 @@
     fail('Incompatible options: There are multiple execstop values and Type is not "oneshot"')
   }
 
+  # TODO: puppet4 / puppet 6 compatibility
+  # if(size($unset_env_vars)>0)
+  # {
+  #   if(defined($::eyp_systemd_release))
+  #   {
+  #     $systemd_release=0+$::eyp_systemd_release
+  #
+  #     if($systemd_release < 235)
+  #     {
+  #       fail("ERROR: UnsetEnvironment is not available for systemd < 235 - current release: ${systemd_release}")
+  #     }
+  #   }
+  # }
+
   # if($restart!=undef)
   # {
   #   # Takes one of no, on-success, on-failure, on-abnormal, on-watchdog, on-abort, or always.
diff --git a/manifests/service/dropin.pp b/manifests/service/dropin.pp
index cc0e78b..ad24464 100644
--- a/manifests/service/dropin.pp
+++ b/manifests/service/dropin.pp
@@ -19,6 +19,7 @@
                                   $remain_after_exit           = undef,
                                   $type                        = undef,
                                   $env_vars                    = [],
+                                  $unset_env_vars              = [],
                                   $environment_files           = [],
                                   $permissions_start_only      = undef,
                                   $timeoutstartsec             = undef,
@@ -79,6 +80,20 @@
   #   validate_re($restart, [ '^no$', '^on-success$', '^on-failure$', '^on-abnormal$', '^on-watchdog$', '^on-abort$', '^always$'], "Not a supported restart type: ${restart} - Takes one of no, on-success, on-failure, on-abnormal, on-watchdog, on-abort, or always")
   # }
 
+  # TODO: puppet4 / puppet 6 compatibility
+  # if(size($unset_env_vars)>0)
+  # {
+  #   if(defined($::eyp_systemd_release))
+  #   {
+  #     $systemd_release=0+$::eyp_systemd_release
+  #
+  #     if($systemd_release < 235)
+  #     {
+  #       fail("ERROR: UnsetEnvironment is not available for systemd < 235 - current release: ${systemd_release}")
+  #     }
+  #   }
+  # }
+
   if versioncmp($::puppetversion, '4.0.0') >= 0
   {
     contain ::systemd
diff --git a/manifests/tmpfile.pp b/manifests/tmpfile.pp
new file mode 100644
index 0000000..9f459c8
--- /dev/null
+++ b/manifests/tmpfile.pp
@@ -0,0 +1,2 @@
+# TODO:
+# https://manpages.debian.org/stretch/systemd/tmpfiles.d.5.en.html
diff --git a/metadata.json b/metadata.json
index 674b475..1357367 100644
--- a/metadata.json
+++ b/metadata.json
@@ -1,6 +1,6 @@
 {
   "name": "eyp-systemd",
-  "version": "0.2.11",
+  "version": "0.2.12",
   "author": "eyp",
   "summary": "management of systemd services, services dropins, sockets, timers, mounts, timesyncd, journald, logind and resolved",
   "license": "Apache-2.0",
diff --git a/templates/section/service.erb b/templates/section/service.erb
index 44ee68c..959d4b2 100644
--- a/templates/section/service.erb
+++ b/templates/section/service.erb
@@ -106,6 +106,11 @@ Type=<%= @type %>
 Environment=<%= env %>
   <%- end -%>
 <% end -%>
+<% if @unset_env_vars.any? -%>
+  <%- @unset_env_vars.each do |env| -%>
+UnsetEnvironment=<%= env %>
+  <%- end -%>
+<% end -%>
 <% if @environment_files.any? -%>
   <%- @environment_files.each do |env_file| -%>
 EnvironmentFile=<%= env_file %>