diff --git a/Multilingual XML FileType/Multilingual.XML.FileType/BatchTasks/ExportBatchTask.cs b/Multilingual XML FileType/Multilingual.XML.FileType/BatchTasks/ExportBatchTask.cs
index 417644a6f3..dbcb93395d 100644
--- a/Multilingual XML FileType/Multilingual.XML.FileType/BatchTasks/ExportBatchTask.cs	
+++ b/Multilingual XML FileType/Multilingual.XML.FileType/BatchTasks/ExportBatchTask.cs	
@@ -9,6 +9,7 @@
 using System.Xml;
 using Multilingual.XML.FileType.BatchTasks.Pages;
 using Multilingual.XML.FileType.BatchTasks.Settings;
+using Multilingual.XML.FileType.Extensions;
 using Multilingual.XML.FileType.FileType.Processors;
 using Multilingual.XML.FileType.FileType.Settings;
 using Multilingual.XML.FileType.Models;
@@ -220,6 +221,8 @@ public override void TaskComplete()
 					outputDocument.Load(outputXmlReader);
 
 					var nsmgr = new XmlNamespaceManager(outputDocument.NameTable);
+					outputDocument.AddAllNamespaces(nsmgr);
+
 					var namespaceUri = _defaultNamespaceHelper.GetXmlNameSpaceUri(
 						multilingualFileInfo.MultilingualFilePath, multilingualFileInfo.FileEncoding);
 					if (!string.IsNullOrEmpty(namespaceUri))
@@ -288,8 +291,8 @@ public override void TaskComplete()
 							: multilingualFileInfo.TargetLanguage.XPath;
 
 
-						var outputXmlNode = outputNode.SelectSingleNode(outputlanguagePath, nsmgr);
-						var multilingualXmlNode = multilingualNode.SelectSingleNode(outputlanguagePath, nsmgr);
+						var outputXmlNode = outputNode.SafeSelectSingleNode(outputlanguagePath, nsmgr);
+						var multilingualXmlNode = multilingualNode.SafeSelectSingleNode(outputlanguagePath, nsmgr);
 
 						if (multilingualXmlNode == null)
 						{
diff --git a/Multilingual XML FileType/Multilingual.XML.FileType/BatchTasks/ImportBatchTask.cs b/Multilingual XML FileType/Multilingual.XML.FileType/BatchTasks/ImportBatchTask.cs
index 2c198cd595..d62e2563fa 100644
--- a/Multilingual XML FileType/Multilingual.XML.FileType/BatchTasks/ImportBatchTask.cs	
+++ b/Multilingual XML FileType/Multilingual.XML.FileType/BatchTasks/ImportBatchTask.cs	
@@ -276,7 +276,7 @@ private List<IParagraphUnit> AlignParagraphUnits(IReadOnlyList<MultilingualParag
 						// Target segmentation is unknown at this point.
 						// TODO: investigate if we can run pretranslation task reverting the language direction
 						for (var m = 0; m < paragraphUnitInfo.SegmentPairs.Count; m++)
-						{
+					{
 							var originalSegmentPairInfo = paragraphUnitInfo.SegmentPairs[m];
 							var segmentPairProperties = originalSegmentPairInfo.SegmentPair.Properties.Clone() as ISegmentPairProperties;
 							var sourceSegment = _segmentBuilder.CreateSegment(segmentPairProperties);
@@ -284,6 +284,11 @@ private List<IParagraphUnit> AlignParagraphUnits(IReadOnlyList<MultilingualParag
 
 							foreach (var item in originalSegmentPairInfo.SegmentPair.Source)
 							{
+								if (item is IPlaceholderTag placeholder)
+								{
+									EnsureTagSubSegments(placeholder, paragraphUnitInfo);
+								}
+
 								sourceSegment.Add(item.Clone() as IAbstractMarkupData);
 							}
 
@@ -291,7 +296,12 @@ private List<IParagraphUnit> AlignParagraphUnits(IReadOnlyList<MultilingualParag
 							{
 								foreach (var item in updatedParagraphUnitInfo.ParagraphUnit.Source)
 								{
-									targetSegment.Add(item.Clone() as IAbstractMarkupData);
+                                    if (item is IPlaceholderTag placeholder)
+                                    {
+										EnsureTagSubSegments(placeholder, paragraphUnitInfo);
+                                    }
+
+                                    targetSegment.Add(item.Clone() as IAbstractMarkupData);
 								}
 							}
 
@@ -400,7 +410,15 @@ private List<IParagraphUnit> AlignParagraphUnits(IReadOnlyList<MultilingualParag
 			return paragraphUnits;
 		}
 
-		private void UpdateSegments(IAbstractMarkupDataContainer container, IEnumerable<ISegmentPair> segmentPairs, bool isSource)
+        private void EnsureTagSubSegments(IPlaceholderTag placeholder, ParagraphUnitInfo paragraphUnitInfo)
+        {
+            foreach (var subSegment in placeholder.SubSegments)
+            {
+                subSegment.ParagraphUnitId = new ParagraphUnitId(paragraphUnitInfo.ParagraphUnitId);
+            }
+        }
+
+        private void UpdateSegments(IAbstractMarkupDataContainer container, IEnumerable<ISegmentPair> segmentPairs, bool isSource)
 		{
 			for (var index = 0; index < container.Count; index++)
 			{
diff --git a/Multilingual XML FileType/Multilingual.XML.FileType/Extensions/XMLDocumentExtensions.cs b/Multilingual XML FileType/Multilingual.XML.FileType/Extensions/XMLDocumentExtensions.cs
new file mode 100644
index 0000000000..4588344dbe
--- /dev/null
+++ b/Multilingual XML FileType/Multilingual.XML.FileType/Extensions/XMLDocumentExtensions.cs	
@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Xml;
+
+namespace Multilingual.XML.FileType.Extensions
+{
+    public static class XMLDocumentExtensions
+    {
+        public static void AddAllNamespaces(this XmlDocument doc, XmlNamespaceManager nsmgr)
+        {
+            var root = doc.DocumentElement;
+            if (root == null) return;
+
+            foreach (XmlAttribute attr in root.Attributes)
+            {
+                if (attr.Prefix == "xmlns")
+                {
+                    nsmgr.AddNamespace(attr.LocalName, attr.Value);
+                }
+                else if (attr.Name == "xmlns")
+                {
+                    nsmgr.AddNamespace(string.Empty, attr.Value); // default namespace
+                }
+            }
+        }
+
+        public static XmlNode SafeSelectSingleNode(this XmlNode node, string path, XmlNamespaceManager nsmgr)
+        {
+            if (string.IsNullOrWhiteSpace(path))
+                return null;
+
+            if (path.TrimStart().StartsWith("["))
+                path = "(.)" + path;  // parentheses make it valid for .NET XPath
+
+            return node.SelectSingleNode(path, nsmgr);
+        }
+    }
+}
diff --git a/Multilingual XML FileType/Multilingual.XML.FileType/Multilingual.XML.FileType.csproj b/Multilingual XML FileType/Multilingual.XML.FileType/Multilingual.XML.FileType.csproj
index 6214a14156..7a05000558 100644
--- a/Multilingual XML FileType/Multilingual.XML.FileType/Multilingual.XML.FileType.csproj	
+++ b/Multilingual XML FileType/Multilingual.XML.FileType/Multilingual.XML.FileType.csproj	
@@ -1,9 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
 	<PropertyGroup>
 		<TargetFramework>net48</TargetFramework>
-		<TradosFolder>C:\Program Files (x86)\Trados\Trados Studio\Studio18beta</TradosFolder>
+		<TradosFolder>C:\Program Files (x86)\Trados\Trados Studio\Studio18</TradosFolder>
 		<GenerateAssemblyInfo>false</GenerateAssemblyInfo>
-		<PluginDeploymentPath>$(AppData)\Trados\Trados Studio\18beta\Plugins</PluginDeploymentPath>
+		<PluginDeploymentPath>$(AppData)\Trados\Trados Studio\18\Plugins</PluginDeploymentPath>
 		<UseWindowsForms>true</UseWindowsForms>
 		<UseWPF>true</UseWPF>
 		<ImportWindowsDesktopTargets>true</ImportWindowsDesktopTargets>
diff --git a/Multilingual XML FileType/Multilingual.XML.FileType/Properties/AssemblyInfo.cs b/Multilingual XML FileType/Multilingual.XML.FileType/Properties/AssemblyInfo.cs
index 140df90cd1..c73ebaacb0 100644
--- a/Multilingual XML FileType/Multilingual.XML.FileType/Properties/AssemblyInfo.cs	
+++ b/Multilingual XML FileType/Multilingual.XML.FileType/Properties/AssemblyInfo.cs	
@@ -28,4 +28,4 @@
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
 [assembly: AssemblyVersion("3.0.0.0")]
-[assembly: AssemblyFileVersion("3.1.1.0")]
+[assembly: AssemblyFileVersion("3.1.2.1")]
diff --git a/Multilingual XML FileType/Multilingual.XML.FileType/Services/BilingualParser.cs b/Multilingual XML FileType/Multilingual.XML.FileType/Services/BilingualParser.cs
index 36c7620559..c734a0a066 100644
--- a/Multilingual XML FileType/Multilingual.XML.FileType/Services/BilingualParser.cs	
+++ b/Multilingual XML FileType/Multilingual.XML.FileType/Services/BilingualParser.cs	
@@ -177,6 +177,7 @@ public bool ParseNext()
 
             _document.Load(_xmlReader);
             _nsmgr = new XmlNamespaceManager(_document.NameTable);
+            _document.AddAllNamespaces(_nsmgr);
 
             UpdateLanguageMappingSettings(_nsmgr);
 
@@ -195,7 +196,7 @@ public bool ParseNext()
 
                 var xmlNode = nodes[index];
 
-                var sourceXmlNode = xmlNode.SelectSingleNode(_sourceLanguage.XPath, _nsmgr);
+                var sourceXmlNode = xmlNode.SafeSelectSingleNode(_sourceLanguage.XPath, _nsmgr);
                 var childNode = sourceXmlNode?.FirstChild;
                 var isCdata = childNode?.NodeType == XmlNodeType.CDATA;
 
@@ -237,7 +238,7 @@ private List<XmlNode> GetParagraphLevelCommentNodes(XmlNode xmlNode)
             var allSegmentCommentXmlNodes = new List<XmlNode>();
             foreach (var languageMappingLanguage in LanguageMappingSettings.LanguageMappingLanguages)
             {
-                var languageXmlNode = xmlNode.SelectSingleNode(languageMappingLanguage.XPath, _nsmgr);
+                var languageXmlNode = xmlNode.SafeSelectSingleNode(languageMappingLanguage.XPath, _nsmgr);
                 var languageComments = languageXmlNode?.SelectNodes(".//" + CommentMappingSettings.CommentElementName, _nsmgr);
                 if (languageComments != null)
                 {
diff --git a/Multilingual XML FileType/Multilingual.XML.FileType/Services/BilingualWriter.cs b/Multilingual XML FileType/Multilingual.XML.FileType/Services/BilingualWriter.cs
index cd87b4fdfd..9494183ca9 100644
--- a/Multilingual XML FileType/Multilingual.XML.FileType/Services/BilingualWriter.cs	
+++ b/Multilingual XML FileType/Multilingual.XML.FileType/Services/BilingualWriter.cs	
@@ -12,6 +12,7 @@
 using Sdl.FileTypeSupport.Framework.BilingualApi;
 using Sdl.FileTypeSupport.Framework.NativeApi;
 using Sdl.FileTypeSupport.Framework.IntegrationApi;
+using Multilingual.XML.FileType.Extensions;
 
 namespace Multilingual.XML.FileType.Services
 {
@@ -167,8 +168,9 @@ public void SetFileProperties(IFileProperties fileInfo)
 			_targetDocument.Load(_xmlReader);
 
 			_nsmgr = new XmlNamespaceManager(_targetDocument.NameTable);
+			_targetDocument.AddAllNamespaces(_nsmgr);
 
-			if (_originalFileProperties.FileSnifferInfo != null && _originalFileProperties.FileSnifferInfo.MetaDataContainsKey(Constants.DefaultNamespace))
+            if (_originalFileProperties.FileSnifferInfo != null && _originalFileProperties.FileSnifferInfo.MetaDataContainsKey(Constants.DefaultNamespace))
 			{
 				var namespaceUri = _originalFileProperties.FileSnifferInfo.GetMetaData(Constants.DefaultNamespace);
 				if (!string.IsNullOrEmpty(namespaceUri))
@@ -439,7 +441,7 @@ private XmlNode GetXmlNode(bool isSource)
 
 		private XmlNode GetXmlUnitNode(XmlNode xmlUnit, string xPath)
 		{
-			var xmlNode = xmlUnit.SelectSingleNode(xPath, _nsmgr);
+			var xmlNode = xmlUnit.SafeSelectSingleNode(xPath, _nsmgr);
 			if (xmlNode == null)
 			{
 				xmlNode = _xmlNodeService.AddXmlNode(xmlUnit, xPath);
diff --git a/Multilingual XML FileType/Multilingual.XML.FileType/Services/DefaultNamespaceHelper.cs b/Multilingual XML FileType/Multilingual.XML.FileType/Services/DefaultNamespaceHelper.cs
index d1e2c89117..88219689bc 100644
--- a/Multilingual XML FileType/Multilingual.XML.FileType/Services/DefaultNamespaceHelper.cs	
+++ b/Multilingual XML FileType/Multilingual.XML.FileType/Services/DefaultNamespaceHelper.cs	
@@ -16,7 +16,25 @@ public DefaultNamespaceHelper(XmlReaderFactory xmlReaderFactory)
 			_xmlReaderFactory = xmlReaderFactory;
 		}
 
-		public string GetXmlNameSpaceUri(string filePath, Encoding encoding)
+        public void AddAllNamespacesFromDocument(XmlDocument doc, XmlNamespaceManager nsmgr)
+        {
+            var root = doc.DocumentElement;
+            if (root == null) return;
+
+            foreach (XmlAttribute attr in root.Attributes)
+            {
+                if (attr.Prefix == "xmlns")
+                {
+                    nsmgr.AddNamespace(attr.LocalName, attr.Value);
+                }
+                else if (attr.Name == "xmlns")
+                {
+                    nsmgr.AddNamespace(string.Empty, attr.Value); // default namespace
+                }
+            }
+        }
+
+        public string GetXmlNameSpaceUri(string filePath, Encoding encoding)
 		{
 			string namespaceUri;
 			using (var fs = new FileStream(filePath, FileMode.Open))
diff --git a/Multilingual XML FileType/Multilingual.XML.FileType/Services/XMLFileSniffer.cs b/Multilingual XML FileType/Multilingual.XML.FileType/Services/XMLFileSniffer.cs
index 52b3d23a07..65e84aa7b4 100644
--- a/Multilingual XML FileType/Multilingual.XML.FileType/Services/XMLFileSniffer.cs	
+++ b/Multilingual XML FileType/Multilingual.XML.FileType/Services/XMLFileSniffer.cs	
@@ -2,6 +2,7 @@
 using System.Linq;
 using System.Text;
 using System.Xml;
+using Multilingual.XML.FileType.Extensions;
 using Multilingual.XML.FileType.FileType.Settings;
 using Sdl.Core.Globalization;
 using Sdl.Core.Settings;
@@ -86,7 +87,9 @@ private bool IsFileSupported(string filePath, string namespaceUri, Encoding enco
 					document.Load(reader);
 
 					var nsmgr = new XmlNamespaceManager(document.NameTable);
-					if (!string.IsNullOrEmpty(namespaceUri))
+					document.AddAllNamespaces(nsmgr);
+
+                    if (!string.IsNullOrEmpty(namespaceUri))
 					{
 						var defaultNameSpace = new XmlNameSpace { Name = Constants.DefaultNamespace, Value = namespaceUri };
 						_defaultNamespaceHelper.AddXmlNameSpacesFromDocument(nsmgr, document, defaultNameSpace);
@@ -107,14 +110,19 @@ private bool IsFileSupported(string filePath, string namespaceUri, Encoding enco
 					}
 
 					var nodes = document.SelectNodes(_languageMappingSettings.LanguageMappingLanguagesXPath, nsmgr);
-					var node = nodes?.Item(0);
-
-					supported = _languageMappingSettings.LanguageMappingLanguages.Select(language =>
-						node?.SelectSingleNode(language.XPath, nsmgr)).Any(target => target != null);
+					foreach (XmlNode node in nodes)
+					{
+						if (_languageMappingSettings.LanguageMappingLanguages.Select(language =>
+                        node?.SafeSelectSingleNode(language.XPath, nsmgr)).Any(target => target != null) == true)
+						{
+							return true;
+						}
+						
+					}
 				}
 			}
 
-			return supported;
+			return false;
 		}
 	}
 }
diff --git a/Multilingual XML FileType/Multilingual.XML.FileType/Services/XmlNodeService.cs b/Multilingual XML FileType/Multilingual.XML.FileType/Services/XmlNodeService.cs
index 56c6b749a2..a31fbcc853 100644
--- a/Multilingual XML FileType/Multilingual.XML.FileType/Services/XmlNodeService.cs	
+++ b/Multilingual XML FileType/Multilingual.XML.FileType/Services/XmlNodeService.cs	
@@ -1,4 +1,5 @@
-using System;
+using Multilingual.XML.FileType.Extensions;
+using System;
 using System.Collections.Generic;
 using System.Text.RegularExpressions;
 using System.Xml;
@@ -50,12 +51,12 @@ public XmlNode AddXmlNode(XmlNode xmlUnit, string xPath)
 
 				var queryNode = GetQueryNode(xmlNodeName, validAttributes);
 
-				var existingNode = xmlNode.SelectSingleNode(queryNode, _nsmgr);
+				var existingNode = xmlNode.SafeSelectSingleNode(queryNode, _nsmgr);
 				if (existingNode == null && !string.IsNullOrEmpty(normalizedXmlNodeName))
 				{
 					xmlNodeName = normalizedXmlNodeName;
 					queryNode = GetQueryNode(normalizedXmlNodeName, validAttributes);
-					existingNode = xmlNode.SelectSingleNode(queryNode, _nsmgr);
+					existingNode = xmlNode.SafeSelectSingleNode(queryNode, _nsmgr);
 				}
 				if (existingNode == null)
 				{
diff --git a/Multilingual XML FileType/Multilingual.XML.FileType/pluginpackage.manifest.xml b/Multilingual XML FileType/Multilingual.XML.FileType/pluginpackage.manifest.xml
index 8bf95e3e93..2b9dbf5e67 100644
--- a/Multilingual XML FileType/Multilingual.XML.FileType/pluginpackage.manifest.xml	
+++ b/Multilingual XML FileType/Multilingual.XML.FileType/pluginpackage.manifest.xml	
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <PluginPackage xmlns="http://www.sdl.com/Plugins/PluginPackage/1.0">
 	<PlugInName>Multilingual XML FileType</PlugInName>
-	<Version>3.1.1.0</Version>
+	<Version>3.1.2.1</Version>
 	<Description>Multilingual XML File Type</Description>
 	<Author>Trados AppStore Team</Author>
 	<RequiredProduct name="TradosStudio" minversion="18.1" maxversion="18.1.9"/>