diff --git a/C4.puml b/C4.puml
index 3ee95ba..e7cead3 100644
--- a/C4.puml
+++ b/C4.puml
@@ -48,6 +48,8 @@ rectangle C4VersionDetailsArea <<legendArea>> [
 !global $LEGEND_DOTTED_LINE = "(dotted) "
 !global $LEGEND_DASHED_LINE = "(dashed) "
 !global $LEGEND_BOLD_LINE = "(bold) "
+!global $LEGEND_DASHED_BOUNDARY = "boundary (dashed) "
+!global $LEGEND_DASHED_TRANSPARENT_BOUNDARY = "boundary (dashed, transparent) "
 
 !global $SKETCH_FOOTER_WARNING = "Warning:"
 !global $SKETCH_FOOTER_TEXT = "Created for discussion, needs to be validated"
@@ -115,21 +117,19 @@ skinparam person {
 }
 
 ' Some boundary skinparams have to be set as package skinparams too (PlantUML uses internal packages)
-skinparam package {
+' UpdateBoundaryStyle() called in boundary section below
+skinparam rectangle<<boundary>> {
+    Shadowing false
     StereotypeFontSize 6
     StereotypeFontColor $BOUNDARY_BG_COLOR
-    FontStyle plain
-    BackgroundColor $BOUNDARY_BG_COLOR
+    BorderStyle dashed
 }
 
-skinparam rectangle<<boundary>> {
-    Shadowing false
+skinparam package {
     StereotypeFontSize 6
     StereotypeFontColor $BOUNDARY_BG_COLOR
-    FontColor $BOUNDARY_COLOR
-    BorderColor $BOUNDARY_COLOR
+    FontStyle plain
     BackgroundColor $BOUNDARY_BG_COLOR
-    BorderStyle dashed
 }
 
 ' Legend and Tags
@@ -265,7 +265,7 @@ skinparam rectangle<<boundary>> {
 !function $elementTagSkinparams($element, $tagStereo, $bgColor, $fontColor, $borderColor, $shadowing, $shape)
   !$elementSkin = "skinparam " + $element + "<<" + $tagStereo + ">> {" + %newline()
   !if ($fontColor != "")
-    !if ($tagStereo != "boundary")
+    !if (%strpos($tagStereo, "boundary") < 0)
       !$elementSkin = $elementSkin + "    StereotypeFontColor " + $fontColor + %newline()
     !endif
     !$elementSkin = $elementSkin + "    FontColor " + $fontColor + %newline()
@@ -304,9 +304,9 @@ skinparam rectangle<<boundary>> {
   ' actor has style awesome, therefore $fontColor is ignored and text uses $bgColor too
   !$tagSkin = $tagSkin + $elementTagSkinparams("actor", $tagStereo, $bgColor, $bgColor, $borderColor, $shadowing, "")
   !$tagSkin = $tagSkin + $elementTagSkinparams("person", $tagStereo, $bgColor, $fontColor, $borderColor, $shadowing, "")
-  !if ($tagStereo == "boundary" && $bgColor != "")
-    !$tagSkin = $tagSkin + "skinparam package<<boundary>>StereotypeFontColor " + $bgColor + %newline()
-    !$tagSkin = $tagSkin + "skinparam rectangle<<boundary>>StereotypeFontColor " + $bgColor + %newline()
+  !if (%strpos($tagStereo, "boundary") >= 0 && $bgColor != "")
+    !$tagSkin = $tagSkin + "skinparam package<<" + $tagStereo + ">>StereotypeFontColor " + $bgColor + %newline()
+    !$tagSkin = $tagSkin + "skinparam rectangle<<" + $tagStereo + ">>StereotypeFontColor " + $bgColor + %newline()
   !endif
 $tagSkin
 !endprocedure
@@ -499,7 +499,26 @@ $elementSkin
     !$tagEntry = $tagEntry + $getSprite($legendSprite) + " "
   !endif
   !if ($legendText == "")
-    !$tagEntry = $tagEntry + " " + $tagStereo + " "
+    !if ($tagStereo == "boundary")
+      !if ($bgColor == "#00000000" || %lower($bgColor) == "transparent")
+        !$tagEntry = $tagEntry + " " + $LEGEND_DASHED_TRANSPARENT_BOUNDARY
+      !else
+        !$tagEntry = $tagEntry + " " + $LEGEND_DASHED_BOUNDARY
+      !endif
+    !elseif (%strpos($tagStereo, "boundary") >= 0)
+      ' if contains/ends with _boundary remove _boundary and add "boundary (dashed)"
+      !$pos = %strpos($tagStereo, "_boundary")
+      !if ($pos > 0)
+        !$tagEntry = $tagEntry + " " + %substr($tagStereo, 0 ,$pos)
+        !if ($bgColor == "#00000000" || %lower($bgColor) == "transparent")
+          !$tagEntry = $tagEntry + " " + $LEGEND_DASHED_TRANSPARENT_BOUNDARY
+        !else
+          !$tagEntry = $tagEntry + " " + $LEGEND_DASHED_BOUNDARY
+        !endif
+      !endif
+    !else
+      !$tagEntry = $tagEntry + " " + $tagStereo + " "
+    !endif
     !if ($shadowing == "true")
       !$tagEntry = $tagEntry + $LEGEND_SHADOW_TEXT
     !endif
@@ -1032,6 +1051,43 @@ $getLegendArea($alias, $hideStereotype)
 ' Boundaries
 ' ##################################
 
+!unquoted procedure UpdateBoundaryStyle($elementName="", $bgColor="", $fontColor="", $borderColor="", $shadowing="", $shape="", $type="", $legendText="")
+  !if ($elementName != "")
+    !$elementBoundary = $elementName + '_boundary'
+    UpdateElementStyle($elementBoundary, $bgColor, $fontColor, $borderColor, $shadowing, $shape, "", $type, $legendText, "")
+  !else
+    UpdateElementStyle("boundary", $bgColor, $fontColor, $borderColor, $shadowing, $shape, "", $type, $legendText, "")
+    ' simulate color inheritance
+    UpdateBoundaryStyle("enterprise", $bgColor, $fontColor, $borderColor, $shadowing, $shape, "Enterprise", "")
+    UpdateBoundaryStyle("system", $bgColor, $fontColor, $borderColor, $shadowing, $shape, "System", "")
+    UpdateBoundaryStyle("container", $bgColor, $fontColor, $borderColor, $shadowing, $shape, "Container", "")
+  !endif
+!endprocedure
+
+!unquoted procedure AddBoundaryTag($tagStereo, $bgColor="", $fontColor="", $borderColor="", $shadowing="", $shape="", $type="", $legendText="")
+    !$tagBoundary = $tagStereo + '_boundary'
+    AddElementTag($tagBoundary, $bgColor, $fontColor, $borderColor, $shadowing, $shape, "", $type, $legendText, "")
+!endprocedure
+
+' add _boundary to all tags that short tag version can be used
+!unquoted function $addBoundaryPostfix($tags)
+  !if (%strlen($tags) == 0)
+    !return ''
+  !endif
+  !$boundaryTags = ''
+  !$brPos = %strpos($tags, "+")
+  !while ($brPos >= 0)
+    !$tag = %substr($tags, 0, $brPos)
+    !$boundaryTags = $boundaryTags + $tag + '_boundary+'
+    !$tags = %substr($tags, $brPos+1)
+    !$brPos = %strpos($tags, "+")
+  !endwhile
+  !if (%strlen($tags) > 0)
+    !$boundaryTags = $boundaryTags + $tags + '_boundary'
+  !endif
+  !return $boundaryTags
+!endfunction
+
 !function $getBoundary($label, $type)
   !if ($type == "")
     !return '==' + $label
@@ -1042,9 +1098,15 @@ $getLegendArea($alias, $hideStereotype)
 !endfunction
 
 !unquoted procedure Boundary($alias, $label, $type="", $tags="", $link="")
-rectangle "$getBoundary($label, $type)" $toStereos("boundary", $tags) as $alias $getLink($link)
+!$boundaryTags = $addBoundaryPostfix($tags)
+' nodes $type reuses $techn definition of $boundaryTags
+!$type=$toElementArg($type, $boundaryTags, "ElementTagTechn", "boundary")
+rectangle "$getBoundary($label, $type)" $toStereos("boundary", $boundaryTags) as $alias $getLink($link)
 !endprocedure
 
+' Boundary Styling
+UpdateBoundaryStyle("", $bgColor=$BOUNDARY_BG_COLOR, $fontColor=$BOUNDARY_COLOR, $borderColor=$BOUNDARY_COLOR)
+
 ' Relationship
 ' ##################################
 
diff --git a/C4_Component.puml b/C4_Component.puml
index 0dc7953..fcff91d 100644
--- a/C4_Component.puml
+++ b/C4_Component.puml
@@ -37,7 +37,7 @@ UpdateElementStyle("external_component", $EXTERNAL_COMPONENT_BG_COLOR, $COMPONEN
 ' Layout
 ' ##################################
 
-SetDefaultLegendEntries("person\nsystem\ncontainer\ncomponent\nexternal_person\nexternal_system\nexternal_container\nexternal_component")
+SetDefaultLegendEntries("person\nsystem\ncontainer\ncomponent\nexternal_person\nexternal_system\nexternal_container\nexternal_component\nenterprise_boundary\nsystem_boundary\ncontainer_boundary\nboundary")
 
 !procedure LAYOUT_WITH_LEGEND()
 hide stereotype
diff --git a/C4_Container.puml b/C4_Container.puml
index ab642a6..d26cc09 100644
--- a/C4_Container.puml
+++ b/C4_Container.puml
@@ -23,6 +23,8 @@
 UpdateElementStyle("container", $CONTAINER_BG_COLOR, $ELEMENT_FONT_COLOR, $CONTAINER_BORDER_COLOR)
 UpdateElementStyle("external_container", $EXTERNAL_CONTAINER_BG_COLOR, $ELEMENT_FONT_COLOR, $EXTERNAL_CONTAINER_BORDER_COLOR)
 
+UpdateBoundaryStyle("container", $bgColor=$BOUNDARY_BG_COLOR, $fontColor=$BOUNDARY_COLOR, $borderColor=$BOUNDARY_COLOR, $type="Container")
+
 ' shortcuts with default colors
 !unquoted procedure AddContainerTag($tagStereo, $bgColor=$CONTAINER_BG_COLOR, $fontColor=$ELEMENT_FONT_COLOR, $borderColor=$CONTAINER_BORDER_COLOR, $shadowing="", $shape="", $sprite="", $techn="", $legendText="", $legendSprite="")
   AddElementTag($tagStereo, $bgColor, $fontColor, $borderColor, $shadowing, $shape, $sprite, $techn, $legendText, $legendSprite)
@@ -31,10 +33,14 @@ UpdateElementStyle("external_container", $EXTERNAL_CONTAINER_BG_COLOR, $ELEMENT_
   AddElementTag($tagStereo, $bgColor, $fontColor, $borderColor, $shadowing, $shape, $sprite, $techn, $legendText, $legendSprite)
 !endprocedure
 
+!unquoted procedure UpdateContainerBoundaryStyle($bgColor=$BOUNDARY_BG_COLOR, $fontColor=$BOUNDARY_COLOR, $borderColor=$BOUNDARY_COLOR, $shadowing="", $shape="", $type="Container", $legendText="")
+  UpdateBoundaryStyle("container", $bgColor, $fontColor, $borderColor, $shadowing, $shape, $type, $legendText)
+!endprocedure
+
 ' Layout
 ' ##################################
 
-SetDefaultLegendEntries("person\nsystem\ncontainer\nexternal_person\nexternal_system\nexternal_container")
+SetDefaultLegendEntries("person\nsystem\ncontainer\nexternal_person\nexternal_system\nexternal_container\nenterprise_boundary\nsystem_boundary\ncontainer_boundary\nboundary")
 
 !procedure LAYOUT_WITH_LEGEND()
 hide stereotype
@@ -107,5 +113,11 @@ queue "$getContainer($label, $techn, $descr, $sprite)$getProps()" $toStereos("ex
 ' ##################################
 
 !unquoted procedure Container_Boundary($alias, $label, $tags="", $link="")
-Boundary($alias, $label, "Container", $tags, $link)
+  !if ($tags != "")
+    !$allTags = $tags + '+container'
+  !else
+    !$allTags = 'container'
+  !endif
+  ' $type defined via $tag style
+  Boundary($alias, $label, "", $allTags, $link)
 !endprocedure
diff --git a/C4_Context.puml b/C4_Context.puml
index ff23a66..53474e2 100644
--- a/C4_Context.puml
+++ b/C4_Context.puml
@@ -30,6 +30,9 @@ UpdateElementStyle("external_person", $EXTERNAL_PERSON_BG_COLOR, $ELEMENT_FONT_C
 UpdateElementStyle("system", $SYSTEM_BG_COLOR, $ELEMENT_FONT_COLOR, $SYSTEM_BORDER_COLOR)
 UpdateElementStyle("external_system", $EXTERNAL_SYSTEM_BG_COLOR, $ELEMENT_FONT_COLOR, $EXTERNAL_SYSTEM_BORDER_COLOR)
 
+UpdateBoundaryStyle("enterprise", $bgColor=$BOUNDARY_BG_COLOR, $fontColor=$BOUNDARY_COLOR, $borderColor=$BOUNDARY_COLOR, $type="Enterprise")
+UpdateBoundaryStyle("system", $bgColor=$BOUNDARY_BG_COLOR, $fontColor=$BOUNDARY_COLOR, $borderColor=$BOUNDARY_COLOR, $type="System")
+
 ' shortcuts with default colors
 !unquoted procedure AddPersonTag($tagStereo, $bgColor=$PERSON_BG_COLOR, $fontColor=$ELEMENT_FONT_COLOR, $borderColor=$PERSON_BORDER_COLOR, $shadowing="", $shape="", $sprite="", $legendText="", $legendSprite="")
   AddElementTag($tagStereo, $bgColor, $fontColor, $borderColor, $shadowing, $shape, $sprite, "", $legendText, $legendSprite)
@@ -44,6 +47,13 @@ UpdateElementStyle("external_system", $EXTERNAL_SYSTEM_BG_COLOR, $ELEMENT_FONT_C
   AddElementTag($tagStereo, $bgColor, $fontColor, $borderColor, $shadowing, $shape, $sprite, "", $legendText, $legendSprite)
 !endprocedure
 
+!unquoted procedure UpdateEnterpriseBoundaryStyle($bgColor=$BOUNDARY_BG_COLOR, $fontColor=$BOUNDARY_COLOR, $borderColor=$BOUNDARY_COLOR, $shadowing="", $shape="", $type="Enterprise", $legendText="")
+  UpdateBoundaryStyle("enterprise", $bgColor, $fontColor, $borderColor, $shadowing, $shape, $type, $legendText)
+!endprocedure
+!unquoted procedure UpdateSystemBoundaryStyle($bgColor=$BOUNDARY_BG_COLOR, $fontColor=$BOUNDARY_COLOR, $borderColor=$BOUNDARY_COLOR, $shadowing="", $shape="", $type="System", $legendText="")
+  UpdateBoundaryStyle("system", $bgColor, $fontColor, $borderColor, $shadowing, $shape, $type, $legendText)
+!endprocedure
+
 ' Sprites
 ' ##################################
 
@@ -152,7 +162,7 @@ sprite $person2 [48x48/16] {
 ' Layout
 ' ##################################
 
-SetDefaultLegendEntries("person\nsystem\nexternal_person\nexternal_system")
+SetDefaultLegendEntries("person\nsystem\nexternal_person\nexternal_system\nenterprise_boundary\nsystem_boundary\nboundary")
 
 !procedure LAYOUT_WITH_LEGEND()
 hide stereotype
@@ -284,9 +294,21 @@ queue "$getSystem($label, $descr, $sprite)$getProps()" $toStereos("external_syst
 ' ##################################
 
 !unquoted procedure Enterprise_Boundary($alias, $label, $tags="", $link="")
-Boundary($alias, $label, "Enterprise", $tags, $link)
+  !if ($tags != "")
+    !$allTags = $tags + '+enterprise'
+  !else
+    !$allTags = 'enterprise'
+  !endif
+  ' $type defined via $tag style
+  Boundary($alias, $label, "", $allTags, $link)
 !endprocedure
 
 !unquoted procedure System_Boundary($alias, $label, $tags="", $link="")
-Boundary($alias, $label, "System", $tags, $link)
+  !if ($tags != "")
+    !$allTags = $tags + '+system'
+  !else
+    !$allTags = 'system'
+  !endif
+  ' $type defined via $tag style
+  Boundary($alias, $label, "", $allTags, $link)
 !endprocedure
diff --git a/C4_Deployment.puml b/C4_Deployment.puml
index 0f225f2..57ba4e0 100644
--- a/C4_Deployment.puml
+++ b/C4_Deployment.puml
@@ -30,7 +30,7 @@ skinparam rectangle<<node>> {
 ' ##################################
 
 ' comment if node should not be added to legend. No calculated legend extension required
-SetDefaultLegendEntries("person\nsystem\ncontainer\nexternal_person\nexternal_system\nexternal_container\nnode")
+SetDefaultLegendEntries("person\nsystem\ncontainer\nexternal_person\nexternal_system\nexternal_container\nnode\nenterprise_boundary\nsystem_boundary\ncontainer_boundary\nboundary")
 
 ' Line breaks
 ' ##################################
diff --git a/README.md b/README.md
index fdb7d75..02dad6f 100644
--- a/README.md
+++ b/README.md
@@ -462,10 +462,15 @@ Additional tags/stereotypes can be added to the existing element stereotypes (co
   Introduces a new element tag. The styles of the tagged elements are updated and the tag is displayed in the calculated legend.
 * `AddRelTag(tagStereo, ?textColor, ?lineColor, ?lineStyle, ?sprite, ?techn, ?legendText, ?legendSprite)`:
   Introduces a new Relationship tag. The styles of the tagged relationships are updated and the tag is displayed in the calculated legend.
+* `AddBoundaryTag(tagStereo, ?bgColor, ?fontColor, ?borderColor, ?shadowing, ?shape, ?type, ?legendText)`:
+  Introduces a new Boundary tag. The styles of the tagged boundaries are updated and the tag is displayed in the calculated legend.
 * `UpdateElementStyle(elementName, ?bgColor, ?fontColor, ?borderColor, ?shadowing, ?shape, ?sprite, ?techn, ?legendText, ?legendSprite)`:
   This call updates the default style of the elements (component, ...) and creates no additional legend entry.
 * `UpdateRelStyle(textColor, lineColor)`:
   This call updates the default relationship colors and creates no additional legend entry.
+* `UpdateBoundaryStyle(?elementName, ?bgColor, ?fontColor, ?borderColor, ?shadowing, ?shape, ?type, ?legendText)
+  This call updates the default style of the existing boundaries and creates no additional legend entry.
+  If the element name is "" then it updates generic, enterprise, system and container boundary style in on call.
 * `RoundedBoxShape()`: This call returns the name of the rounded box shape and can be used as ?shape argument.
 * `EightSidedShape()`: This call returns the name of the eight sided shape and can be used as ?shape argument.
 * `DashedLine()`: This call returns the name of the dashed line and can be used as ?lineStyle argument.
@@ -498,6 +503,13 @@ Following calls introduces new element tags with element specific default colors
 * `AddNodeTag(tagStereo, ?bgColor, ?fontColor, ?borderColor, ?shadowing, ?shape, ?sprite, ?techn, ?legendText, ?legendSprite)`
   (node specific: $type reuses $techn definition of $tags)
 
+**Boundary specific tag definitions**
+
+Like the element specific tag definitions exist boundary specific calls with their default colors **and type**:
+* `UpdateContainerBoundaryStyle(?bgColor, ?fontColor, ?borderColor, ?shadowing, ?shape, ?type, ?legendText)`
+* `UpdateSystemBoundaryStyle(?bgColor, ?fontColor, ?borderColor, ?shadowing, ?shape, ?type, ?legendText)`
+* `UpdateEnterpriseBoundaryStyle(?bgColor, ?fontColor, ?borderColor, ?shadowing, ?shape, ?type, ?legendText)`
+
 **Comments**
 
 * `SHOW_LEGEND()` supports the customized stereotypes
@@ -616,6 +628,55 @@ SHOW_LEGEND()
 
 ![tags with sprites and custom legend](https://www.plantuml.com/plantuml/png/dLJTRkCs4xttKt2DlN00nyewNxu0HRDOnqwxNJYRr3_DfJ0Inx9QYbH9AevHzDqxf6tHiPMVDbSHvvmpXpE7_c8iQ5iLelKXbwceEBAbjQNv8Oeqh7fPRfTLKXdKgP8MfUsbgeXA0T9nJetb8a-YuVzExztH_7OS5M0iQZgAXyI0NABkbKw_zO7ZWZwPCd1F1-_eCzHWbiYBNF9er-1KbIWDffNExHfqkimjfhRIs3_DYMks1i9rjksYeIeA9RsNu-BSa6SGObCEzH_LOf6d64rHFw8s4GSB2HYCZJ_u_39oaOjteA0iHPw2pPLy6Ko3JB6q9d88EeZtMA_15xd65GZnkTKQS7xpP55B4FVKLyaPP9qsI2NNXQfCZ4-stMKVJKbJnQksCX2xPSI9WFIFU0c-AZ13oMU4lGfKvd3j4zTXJpcjZ5K5waPH0Jh3EDEgAezaiqnZ1XPviowuC3IAGiLpsqsLKFfA8m_2qsQaIK7WrLclVn58HsvSjznOxKUzS-GirTdshbQO3CfotzRnNW-rYSC8nTAT4YaV2VDaNpI4hq4nb5-NTBaq-whke5dHbzYczBee5Gy6q13LGtKY6INmQ0fEVeB22-yYxBYMM4E_glR7mMHozn0FxyPt4ozBrAPIC5GhrOi_Vsdl0UlCRC8Nq-lfr9dtEUgozhLAl378pDN1OphP4ZiXqJlM58ek--LHIGpa-hq4thFirHrHInve7kHSJjV6OX5VgqfoqEjE-ed05jEbrNc2flUxQP_yrMBqLo-kGmbqwo7W0sLny6nHxM_m25tctexCsErlmowRgOBAxBBt5FflWt_oN7cKT3IAc2UaGulqcY3OQ9jF9t-xdluwPXUzYtqrdXmgTNnQ_Ts8z9EBu-QcRVSvc9tt0zj36wn8PVuK1F-kN4jdWasjqXiRIcPgTCtwlVuRHggIW_Khc6_-sms9NJgK3x8RHTYeaflH_DrgqH2EmXEcFpTedDhNsUn-6WH223q_vEY_2Xm6wj-AU9MQiBTXu8Ojj2eOICvMxhaPPfKJeub7tqRNb9vIQSlEpy_-lt4JTCA6dsaTmdPR38Zz_Qt89IkriYfLOjkiVtdswN9hEvw71RvXd53mbliWT-3_eRxy4IvSe7bSxxxE6DRnf7vWeJsLfb_fbszyy_FDzr7dfFK59QyAyGy0 "tags with sprites and custom legend")
 
+**Sample with different boundary tag combinations**
+
+```plantuml
+@startuml
+!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Component.puml
+
+' Update the generic boundary style and the "system", "enterprise", "container" boundaries styles too
+UpdateBoundaryStyle($bgColor="gold", $fontColor="brown", $borderColor="brown")
+' (Re-)Updates the system boundary styles; re-set $bgColor avoids '(no back color)' in legend too
+UpdateSystemBoundaryStyle($bgColor="gold", $fontColor="white", $borderColor="white")
+
+Boundary(b, "A Boundary") {
+}
+
+Container_Boundary(cb, "A Container Boundary") {
+}
+
+System_Boundary(sb, "A System Boundary") {
+}
+
+' defines a new border style incl. new border type
+AddBoundaryTag("repository", $bgColor="green", $fontColor="white", $borderColor="white", $shadowing="true", $shape = RoundedBoxShape(), $type="GitHub repository")
+
+Boundary(c4Respository, "plantuml-stdlib/C4-PlantUML", $tags="repository") {
+  Component(readMe, "README.md", "Markdown")
+}
+
+' boundary tags are internally extended with '_boundary' that it uses a different name space
+' this enables different element and boundary styles for the same tag name
+AddBoundaryTag("v1", $bgColor="lightgreen", $fontColor="green", $borderColor="green")
+AddElementTag("v1", $bgColor="lightred", $fontColor="red", $borderColor="red")
+
+Boundary(anotherBoundary, "Another Boundary", $type="BOUNDARY TYPE", $tags="v1") {
+  Component(anotherComponent, "Another Component", $techn="COMPONENT TYPE", $tags="v1", $descr="Component and boundary use different tag name spaces that both v1 tags can use different styles")
+}
+
+Lay_R(b, cb)
+Lay_R(cb, sb)
+
+Lay_D(b, c4Respository)
+
+Lay_R(c4Respository, anotherBoundary)
+
+SHOW_LEGEND()
+@enduml
+```
+
+![custom border tags](https://www.plantuml.com/plantuml/png/bLHHRzem47xFhxX5bKYa0ghKfqr8fO3QXm8Lj9hwX9puIAmcTcGxfMZQVvyF4vg6RTgUsllkxlEN--wuCPPfMvT5y4N8jAWvGcvjPRuEXvhj1fcmUPtK1dMgf4Lf1wagXrN19FNqZUM5I8QJw_uZGS_pXs79Z4NjeCr4bPMIr5CHVz23vuepYs1pX0mbQf52ech9cTw3iVi2WKb-I8TcxsZAy192Hu2wqi8WHII32TSRDgq2ZMysO9KA_1ktHzer9QAB99keGkbHcAc2EvgBhQCvGebMEqbOeZH7_GcDdUXeXVtOivg3DY-jezny0urzWnQQnu2zAS4Dz2Af867fAwG4npqG4WhCKFAMuFM1z3zaxt9XiIExGUCWQ9YYn0rj34qOnl0Z-1a4asQCcrDXwYjFcRCUB_6ZmVW63vzLzu3Zrl4OO21n1rxcqMPQjK4RjliAWp7d3SiJow9GOwMCiCgHNa9h61fH_liq23KvusedP3OAhQuRg48OmOfUHFVm-vgGA7OvKZCAxuIzhnDegMZFDRrUeMaoRX1_kOcGA5bcHkqleZ41d6uaqiZu71tHQZQUpcU3aWmFvqo_Sh-9DDEFfIC-O9f6QL5BLXHxm7UBz2sm4pQ7tgOfxe7DcGLXeJO7FxZORb6Zj21PYM0gbc90LS80IfOKQ5erM619VvdatQM7hTB-9eZ7QIB2SoFVhZuPM8WijxzpqMDT5pqQ4-lCI_aZgSRkcH3I9IIiRIMJokQecvYscf3s2PoMudRvl9YELo_mzF8uEnbBOZg6Dgmde4LxmWu4cEPo54wMyyVbOhPuEcEc_pcQr2dtZLqpoDQMNwwlvQlnvYVkPNYxydkJCjdfyNRwBNjW-ysAVZVI93u6gOkCYmxXz91hht_SD7MEeZDOLxQ-NtxVFCpkPejf50StABaxcLy0 "custom border tags")
+
 **Custom schema definition**
 
 If the custom (color) schema is defined via `UpdateElementStyle()` then the legend of existing elements is updated too.
diff --git a/percy/TestBoundaryTagSupport.puml b/percy/TestBoundaryTagSupport.puml
new file mode 100644
index 0000000..0458122
--- /dev/null
+++ b/percy/TestBoundaryTagSupport.puml
@@ -0,0 +1,49 @@
+@startuml
+' convert it with additional command line argument -DRELATIVE_INCLUDE="." to use locally
+!if %variable_exists("RELATIVE_INCLUDE")
+  !include ./../C4_Component.puml
+!else
+  !include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Component.puml
+!endif
+
+UpdateBoundaryStyle($bgColor="gold", $fontColor="brown", $borderColor="brown")
+' re-set $bgColor avoids '(no back color)' in legend
+UpdateSystemBoundaryStyle($bgColor="gold", $fontColor="white", $borderColor="white")
+
+AddBoundaryTag("specialSystem", $bgColor="green", $fontColor="white", $borderColor="blue", $shadowing="true", $shape = RoundedBoxShape(), $type="A SPECIAL SYSTEM BOUNDARY")
+AddBoundaryTag("existingContainersBoundary", $bgColor="red", $fontColor="white", $borderColor="white", $type="Existing CONTAINER BOUNDARY", $legendText="container boundary with existing components")
+
+System_Boundary(sb, "A System Boundary") {
+}
+
+System_Boundary(sb1, "Special System 1 Boundary", $tags="specialSystem") {
+  Container_Boundary(cb1, "Container Boundary\nwith tag", $tags="existingContainersBoundary") {
+    Component(e1, "existing 1", "xyz")
+    Component(e2, "existing 2", "xyz")
+  }
+  Container_Boundary(cb2, "A Container Boundary") {
+    Component(c2, "Component", "xyz")
+  }
+}
+
+System_Boundary(sb2, "Special System 2 Boundary", $tags="specialSystem") { 
+}
+
+' boundary tags are internally extended with '_boundary' that it uses a different name space
+' this enables different element and boundary styles for the same tag name
+AddBoundaryTag("v1", $bgColor="lightgreen", $fontColor="green", $borderColor="green")
+AddElementTag("v1", $bgColor="lightred", $fontColor="red", $borderColor="red")
+
+Boundary(anotherBoundary, "Another Boundary", $type="BOUNDARY TYPE", $tags="v1") {
+  Component(anotherComponent, "Another Component", $techn="COMPONENT TYPE", $tags="v1", $descr="Component and boundary use different tag name spaces that both v1 tags can use different styles")
+}
+
+Boundary(aBoundary, "A Boundary") {
+}
+
+Lay_R(sb, sb1)
+Lay_R(sb1, sb2)
+Lay_R(sb2, anotherBoundary)
+
+SHOW_LEGEND()
+@enduml