diff --git a/manifests/classic.pp b/manifests/classic.pp
index f3e9704..a7735db 100644
--- a/manifests/classic.pp
+++ b/manifests/classic.pp
@@ -57,19 +57,16 @@
   $joinou                         = undef,
   Optional[String] $default_realm = undef,
   Array $additional_realms        = [],
-) inherits samba::params{
-
-
-  unless is_domain_name($realm){
+) inherits samba::params {
+  unless ($realm =~ Variant[Stdlib::Fqdn, Stdlib::Dns::Zone]) {
     fail('realm must be a valid domain')
   }
 
-  unless is_domain_name($realm){
-    fail('realm must be a valid domain')
+  unless ($smbname =~ String[1,15]) {
+    fail('smbname too short or too long')
   }
 
-  validate_slength($smbname, 15)
-  unless is_domain_name("${smbname}.${realm}"){
+  unless ("${smbname}.${realm}" =~ Variant[Stdlib::Fqdn, Stdlib::Dns::Zone]) {
     fail('smbname must be a valid domain')
   }
 
@@ -94,6 +91,12 @@
 
   $_default_realm = pick($default_realm, $realmuppercase)
 
+  if $manage_winbind {
+    $services_to_notify = ['SambaSmb', 'SambaWinBind']
+  }
+  else {
+    $services_to_notify = ['SambaSmb']
+  }
 
   file { '/etc/samba/':
     ensure  => 'directory',
@@ -111,7 +114,7 @@
         ensure  => present,
         mode    => '0644',
         content => template("${module_name}/krb5.conf.erb"),
-        notify  => Service['SambaSmb', 'SambaWinBind'],
+        notify  => Service[$services_to_notify];
       }
     }
 
@@ -281,12 +284,6 @@
   $mandatoryglobaloptionsindex = prefix(keys($mandatoryglobaloptions),
     '[global]')
 
-  if $manage_winbind {
-    $services_to_notify = ['SambaSmb', 'SambaWinBind']
-  }
-  else {
-    $services_to_notify = ['SambaSmb']
-  }
   samba::option{ $mandatoryglobaloptionsindex:
     options         => $mandatoryglobaloptions,
     section         => 'global',
diff --git a/manifests/dc.pp b/manifests/dc.pp
index d1859a6..299d810 100644
--- a/manifests/dc.pp
+++ b/manifests/dc.pp
@@ -105,7 +105,7 @@
     fail("role must be in [${checkrolestr}]")
   }
 
-  unless is_domain_name($realm){
+  unless ($realm =~ Variant[Stdlib::Fqdn, Stdlib::Dns::Zone]) {
     fail('realm must be a valid domain')
   }
 
diff --git a/manifests/dc/ppolicy_param.pp b/manifests/dc/ppolicy_param.pp
index f89ccd3..8e18eb3 100644
--- a/manifests/dc/ppolicy_param.pp
+++ b/manifests/dc/ppolicy_param.pp
@@ -6,20 +6,18 @@
   String $value,
 ){
 
-  validate_re(
-    $option,
-    '^--.*$',
-    "option must start with '--' and be \
+  if $option !~ /^--.*$/ {
+    fail("option must start with '--' and be \
 a valid 'samba-tool domain passwordsettings' option",
-  )
+    )
+  }
 
-  validate_re(
-    $show_string,
-    '^.*:$',
-    "show_string must end with ':' \
+  if $show_string !~ /^.*:$/ {
+    fail("show_string must end with ':' \
 and be the string in 'samba-tool domain passwordsettings show' \
 corresponding to option",
-  )
+    )
+  }
 
   exec{"cmd_ppolicy_param ${option}":
     path    => '/bin:/sbin:/usr/bin:/usr/sbin',
diff --git a/manifests/log.pp b/manifests/log.pp
index bf72d0f..b05ba6a 100644
--- a/manifests/log.pp
+++ b/manifests/log.pp
@@ -11,7 +11,7 @@
   $classliststr = join($classlist, ', ')
 
   if $sambaclassloglevel != undef {
-    unless is_hash($sambaclassloglevel)
+    unless $sambaclassloglevel =~ Hash
     and difference(keys($sambaclassloglevel), $classlist) == [] {
       fail("sambaclassloglevel must be a hash with keys in [${classliststr}]")
     }
diff --git a/metadata.json b/metadata.json
index 67e88a4..fb4cafc 100644
--- a/metadata.json
+++ b/metadata.json
@@ -11,7 +11,7 @@
   "dependencies": [
     {
       "name": "puppetlabs-stdlib",
-      "version_requirement": ">= 3.0.0 < 5.0.0"
+      "version_requirement": ">= 9.0.0 < 9.4.0"
     },
     {
       "name": "herculesteam-augeasproviders_pam",
@@ -43,8 +43,8 @@
     {
       "operatingsystem": "Ubuntu",
       "operatingsystemrelease": [
-        "14.04",
-        "16.04"
+        "20.04",
+        "21.04"
       ]
     },
     {
@@ -54,7 +54,7 @@
   "requirements": [
     {
       "name": "puppet",
-      "version_requirement": ">= 4.10.0 < 6.0.0"
+      "version_requirement": ">= 6.0.0 < 9.0.0"
     }
   ]
 }