diff --git a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/context/TerminologyCache.java b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/context/TerminologyCache.java
index acd05391e..ae66e4b1d 100644
--- a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/context/TerminologyCache.java
+++ b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/context/TerminologyCache.java
@@ -1,33 +1,33 @@
 package org.hl7.fhir.r4.context;
 
-/*
-  Copyright (c) 2011+, HL7, Inc.
-  All rights reserved.
-  
-  Redistribution and use in source and binary forms, with or without modification, 
-  are permitted provided that the following conditions are met:
-    
-   * Redistributions of source code must retain the above copyright notice, this 
-     list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above copyright notice, 
-     this list of conditions and the following disclaimer in the documentation 
-     and/or other materials provided with the distribution.
-   * Neither the name of HL7 nor the names of its contributors may be used to 
-     endorse or promote products derived from this software without specific 
-     prior written permission.
-  
-  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
-  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
-  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
-  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
-  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
-  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
-  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
-  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
-  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
-  POSSIBILITY OF SUCH DAMAGE.
-  
- */
+/*
+  Copyright (c) 2011+, HL7, Inc.
+  All rights reserved.
+  
+  Redistribution and use in source and binary forms, with or without modification, 
+  are permitted provided that the following conditions are met:
+    
+   * Redistributions of source code must retain the above copyright notice, this 
+     list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above copyright notice, 
+     this list of conditions and the following disclaimer in the documentation 
+     and/or other materials provided with the distribution.
+   * Neither the name of HL7 nor the names of its contributors may be used to 
+     endorse or promote products derived from this software without specific 
+     prior written permission.
+  
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
+  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
+  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
+  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
+  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
+  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
+  POSSIBILITY OF SUCH DAMAGE.
+  
+ */
 
 
 
@@ -84,16 +84,88 @@ public class TerminologyCache {
   private static final String ENTRY_MARKER = "-------------------------------------------------------------------------------------";
   private static final String BREAK = "####";
 
+  private SystemNameKeyGenerator systemNameKeyGenerator = new SystemNameKeyGenerator();
+
+  protected SystemNameKeyGenerator getSystemNameKeyGenerator() {
+    return systemNameKeyGenerator;
+  }
+
+  public class SystemNameKeyGenerator {
+    public static final String SNOMED_SCT_CODESYSTEM_URL = "http://snomed.info/sct";
+    public static final String RXNORM_CODESYSTEM_URL = "http://www.nlm.nih.gov/research/umls/rxnorm";
+    public static final String LOINC_CODESYSTEM_URL = "http://loinc.org";
+    public static final String UCUM_CODESYSTEM_URL = "http://unitsofmeasure.org";
+
+    public static final String HL7_TERMINOLOGY_CODESYSTEM_BASE_URL = "http://terminology.hl7.org/CodeSystem/";
+    public static final String HL7_SID_CODESYSTEM_BASE_URL = "http://hl7.org/fhir/sid/";
+    public static final String HL7_FHIR_CODESYSTEM_BASE_URL = "http://hl7.org/fhir/";
+
+    public static final String ISO_CODESYSTEM_URN = "urn:iso:std:iso:";
+    public static final String LANG_CODESYSTEM_URN = "urn:ietf:bcp:47";
+    public static final String MIMETYPES_CODESYSTEM_URN = "urn:ietf:bcp:13";
+
+    public static final String _11073_CODESYSTEM_URN = "urn:iso:std:iso:11073:10101";
+    public static final String DICOM_CODESYSTEM_URL = "http://dicom.nema.org/resources/ontology/DCM";
+
+    public String getNameForSystem(String system) {
+      final int lastPipe = system.lastIndexOf('|');
+      final String systemBaseName = lastPipe == -1 ? system : system.substring(0,lastPipe);
+      final String systemVersion = lastPipe == -1 ? null : system.substring(lastPipe + 1);
+
+      if (systemBaseName.equals(SNOMED_SCT_CODESYSTEM_URL))
+        return getVersionedSystem("snomed", systemVersion);
+      if (systemBaseName.equals(RXNORM_CODESYSTEM_URL))
+        return getVersionedSystem("rxnorm", systemVersion);
+      if (systemBaseName.equals(LOINC_CODESYSTEM_URL))
+        return getVersionedSystem("loinc", systemVersion);
+      if (systemBaseName.equals(UCUM_CODESYSTEM_URL))
+        return getVersionedSystem("ucum", systemVersion);
+      if (systemBaseName.startsWith(HL7_SID_CODESYSTEM_BASE_URL))
+        return getVersionedSystem(normalizeBaseURL(HL7_SID_CODESYSTEM_BASE_URL, systemBaseName), systemVersion);
+      if (systemBaseName.equals(_11073_CODESYSTEM_URN))
+        return getVersionedSystem("11073", systemVersion);
+      if (systemBaseName.startsWith(ISO_CODESYSTEM_URN))
+        return getVersionedSystem("iso"+systemBaseName.substring(ISO_CODESYSTEM_URN.length()).replace(":", ""), systemVersion);
+      if (systemBaseName.startsWith(HL7_TERMINOLOGY_CODESYSTEM_BASE_URL))
+        return getVersionedSystem(normalizeBaseURL(HL7_TERMINOLOGY_CODESYSTEM_BASE_URL, systemBaseName), systemVersion);
+      if (systemBaseName.startsWith(HL7_FHIR_CODESYSTEM_BASE_URL))
+        return getVersionedSystem(normalizeBaseURL(HL7_FHIR_CODESYSTEM_BASE_URL, systemBaseName), systemVersion);
+      if (systemBaseName.equals(LANG_CODESYSTEM_URN))
+        return getVersionedSystem("lang", systemVersion);
+      if (systemBaseName.equals(MIMETYPES_CODESYSTEM_URN))
+        return getVersionedSystem("mimetypes", systemVersion);
+      if (systemBaseName.equals(DICOM_CODESYSTEM_URL))
+        return getVersionedSystem("dicom", systemVersion);
+      return getVersionedSystem(systemBaseName.replace("/", "_").replace(":", "_").replace("?", "X").replace("#", "X"), systemVersion);
+    }
+
+    public String normalizeBaseURL(String baseUrl, String fullUrl) {
+      return fullUrl.substring(baseUrl.length()).replace("/", "");
+    }
+
+    public String getVersionedSystem(String baseSystem, String version) {
+      if (version != null) {
+        return baseSystem + "_" + version;
+      }
+      return baseSystem;
+    }
+  }
+
   public class CacheToken {
     private String name;
     private String key;
     private String request;
     public void setName(String n) {
+      String systemName = getSystemNameKeyGenerator().getNameForSystem(n);
       if (name == null)
-        name = n;
-      else if (!n.equals(name))
+        name = systemName;
+      else if (!systemName.equals(name))
         name = NAME_FOR_NO_SYSTEM;
     }
+
+    public String getName() {
+      return name;
+    }
   }
 
   private class CacheEntry {
@@ -126,7 +198,7 @@ public class TerminologyCache {
   public CacheToken generateValidationToken(ValidationOptions options, Coding code, ValueSet vs) {
     CacheToken ct = new CacheToken();
     if (code.hasSystem())
-      ct.name = getNameForSystem(code.getSystem());
+      ct.name = getSystemNameKeyGenerator().getNameForSystem(code.getSystem());
     else
       ct.name = NAME_FOR_NO_SYSTEM;
     JsonParser json = new JsonParser();
@@ -145,7 +217,7 @@ public class TerminologyCache {
     CacheToken ct = new CacheToken();
     for (Coding c : code.getCoding()) {
       if (c.hasSystem())
-        ct.setName(getNameForSystem(c.getSystem()));
+        ct.setName(c.getSystem());
     }
     JsonParser json = new JsonParser();
     json.setOutputStyle(OutputStyle.PRETTY);
@@ -176,13 +248,13 @@ public class TerminologyCache {
     ValueSet vsc = getVSEssense(vs);
     for (ConceptSetComponent inc : vs.getCompose().getInclude())
       if (inc.hasSystem())
-        ct.setName(getNameForSystem(inc.getSystem()));
+        ct.setName(inc.getSystem());
     for (ConceptSetComponent inc : vs.getCompose().getExclude())
       if (inc.hasSystem())
-        ct.setName(getNameForSystem(inc.getSystem()));
+        ct.setName(inc.getSystem());
     for (ValueSetExpansionContainsComponent inc : vs.getExpansion().getContains())
       if (inc.hasSystem())
-        ct.setName(getNameForSystem(inc.getSystem()));
+        ct.setName(inc.getSystem());
     JsonParser json = new JsonParser();
     json.setOutputStyle(OutputStyle.PRETTY);
     try {
@@ -194,34 +266,6 @@ public class TerminologyCache {
     return ct;
   }
 
-  private String getNameForSystem(String system) {
-    if (system.equals("http://snomed.info/sct"))
-      return "snomed";
-    if (system.equals("http://www.nlm.nih.gov/research/umls/rxnorm"))
-      return "rxnorm";
-    if (system.equals("http://loinc.org"))
-      return "loinc";
-    if (system.equals("http://unitsofmeasure.org"))
-      return "ucum";
-    if (system.startsWith("http://hl7.org/fhir/sid/"))
-      return system.substring(24).replace("/", "");
-    if (system.startsWith("urn:iso:std:iso:"))
-      return "iso"+system.substring(16).replace(":", "");
-    if (system.startsWith("http://terminology.hl7.org/CodeSystem/"))
-      return system.substring(38).replace("/", "");
-    if (system.startsWith("http://hl7.org/fhir/"))
-      return system.substring(20).replace("/", "");
-    if (system.equals("urn:ietf:bcp:47"))
-      return "lang";
-    if (system.equals("urn:ietf:bcp:13"))
-      return "mimetypes";
-    if (system.equals("urn:iso:std:iso:11073:10101"))
-      return "11073";
-    if (system.equals("http://dicom.nema.org/resources/ontology/DCM"))
-      return "dicom";
-    return system.replace("/", "_").replace(":", "_");
-  }
-
   public NamedCache getNamedCache(CacheToken cacheToken) {
     NamedCache nc = caches.get(cacheToken.name);
     if (nc == null) {
diff --git a/org.hl7.fhir.r4/src/test/java/org/hl7/fhir/r4/context/CacheTestUtils.java b/org.hl7.fhir.r4/src/test/java/org/hl7/fhir/r4/context/CacheTestUtils.java
new file mode 100644
index 000000000..059d2ec0b
--- /dev/null
+++ b/org.hl7.fhir.r4/src/test/java/org/hl7/fhir/r4/context/CacheTestUtils.java
@@ -0,0 +1,8 @@
+package org.hl7.fhir.r4.context;
+
+import org.hl7.fhir.utilities.validation.ValidationOptions;
+
+public class CacheTestUtils {
+    public static final ValidationOptions validationOptions =  new ValidationOptions().guessSystem().setVersionFlexible(false);
+
+}
diff --git a/org.hl7.fhir.r4/src/test/java/org/hl7/fhir/r4/context/TerminologyCacheTests.java b/org.hl7.fhir.r4/src/test/java/org/hl7/fhir/r4/context/TerminologyCacheTests.java
new file mode 100644
index 000000000..89ebbcc6c
--- /dev/null
+++ b/org.hl7.fhir.r4/src/test/java/org/hl7/fhir/r4/context/TerminologyCacheTests.java
@@ -0,0 +1,61 @@
+package org.hl7.fhir.r4.context;
+
+
+import org.hl7.fhir.r4.model.Coding;
+import org.hl7.fhir.r4.model.ValueSet;
+
+import org.hl7.fhir.utilities.tests.ResourceLoaderTests;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+
+public class TerminologyCacheTests implements ResourceLoaderTests {
+
+  private TerminologyCache createTerminologyCache() throws IOException {
+    Object lock = new Object();
+    TerminologyCache terminologyCache = new TerminologyCache(lock, null);
+    return terminologyCache;
+  }
+
+  @ParameterizedTest
+  @CsvSource({
+    "http://terminology.hl7.org/CodeSystem/id,id",
+    "http://hl7.org/fhir/id,id",
+    "http://hl7.org/fhir/sid/id,id",
+    "http://www.nlm.nih.gov/research/umls/rxnorm,rxnorm",
+    "http://snomed.info/sct,snomed",
+    "http://www.nlm.nih.gov/research/umls/rxnorm,rxnorm",
+    "http://loinc.org,loinc",
+    "http://unitsofmeasure.org,ucum",
+    "urn:iso:std:iso:id,isoid",
+    "urn:ietf:bcp:47,lang",
+    "urn:ietf:bcp:13,mimetypes",
+    "urn:iso:std:iso:11073:10101,11073",
+    "my://random/system?with#chars,my___random_systemXwithXchars",
+    "http://dicom.nema.org/resources/ontology/DCM,dicom"
+  })
+  public void testCacheTokenGeneration(String system, String expectedName) throws IOException, URISyntaxException {
+
+    TerminologyCache terminologyCache = createTerminologyCache();
+    ValueSet valueSet = new ValueSet();
+    {
+      Coding coding = new Coding();
+      coding.setSystem(system);
+      TerminologyCache.CacheToken cacheToken = terminologyCache.generateValidationToken(CacheTestUtils.validationOptions,
+        coding, valueSet);
+      assertEquals(expectedName, cacheToken.getName());
+    }
+    {
+      Coding coding = new Coding();
+      coding.setSystem(system + "|dummyVersion");
+      TerminologyCache.CacheToken cacheToken = terminologyCache.generateValidationToken(CacheTestUtils.validationOptions,
+        coding, valueSet);
+      assertEquals(expectedName + "_dummyVersion", cacheToken.getName());
+    }
+  }
+}
diff --git a/org.hl7.fhir.r4b/src/main/java/org/hl7/fhir/r4b/context/TerminologyCache.java b/org.hl7.fhir.r4b/src/main/java/org/hl7/fhir/r4b/context/TerminologyCache.java
index fd6d48de4..4c5ce24b8 100644
--- a/org.hl7.fhir.r4b/src/main/java/org/hl7/fhir/r4b/context/TerminologyCache.java
+++ b/org.hl7.fhir.r4b/src/main/java/org/hl7/fhir/r4b/context/TerminologyCache.java
@@ -1,33 +1,33 @@
 package org.hl7.fhir.r4b.context;
 
-/*
-  Copyright (c) 2011+, HL7, Inc.
-  All rights reserved.
-  
-  Redistribution and use in source and binary forms, with or without modification, 
-  are permitted provided that the following conditions are met:
-    
-   * Redistributions of source code must retain the above copyright notice, this 
-     list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above copyright notice, 
-     this list of conditions and the following disclaimer in the documentation 
-     and/or other materials provided with the distribution.
-   * Neither the name of HL7 nor the names of its contributors may be used to 
-     endorse or promote products derived from this software without specific 
-     prior written permission.
-  
-  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
-  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
-  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
-  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
-  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
-  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
-  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
-  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
-  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
-  POSSIBILITY OF SUCH DAMAGE.
-  
- */
+/*
+  Copyright (c) 2011+, HL7, Inc.
+  All rights reserved.
+  
+  Redistribution and use in source and binary forms, with or without modification, 
+  are permitted provided that the following conditions are met:
+    
+   * Redistributions of source code must retain the above copyright notice, this 
+     list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above copyright notice, 
+     this list of conditions and the following disclaimer in the documentation 
+     and/or other materials provided with the distribution.
+   * Neither the name of HL7 nor the names of its contributors may be used to 
+     endorse or promote products derived from this software without specific 
+     prior written permission.
+  
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
+  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
+  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
+  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
+  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
+  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
+  POSSIBILITY OF SUCH DAMAGE.
+  
+ */
 
 
 
@@ -84,16 +84,88 @@ public class TerminologyCache {
   private static final String ENTRY_MARKER = "-------------------------------------------------------------------------------------";
   private static final String BREAK = "####";
 
+  private SystemNameKeyGenerator systemNameKeyGenerator = new SystemNameKeyGenerator();
+
+  protected SystemNameKeyGenerator getSystemNameKeyGenerator() {
+    return systemNameKeyGenerator;
+  }
+
+  public class SystemNameKeyGenerator {
+    public static final String SNOMED_SCT_CODESYSTEM_URL = "http://snomed.info/sct";
+    public static final String RXNORM_CODESYSTEM_URL = "http://www.nlm.nih.gov/research/umls/rxnorm";
+    public static final String LOINC_CODESYSTEM_URL = "http://loinc.org";
+    public static final String UCUM_CODESYSTEM_URL = "http://unitsofmeasure.org";
+
+    public static final String HL7_TERMINOLOGY_CODESYSTEM_BASE_URL = "http://terminology.hl7.org/CodeSystem/";
+    public static final String HL7_SID_CODESYSTEM_BASE_URL = "http://hl7.org/fhir/sid/";
+    public static final String HL7_FHIR_CODESYSTEM_BASE_URL = "http://hl7.org/fhir/";
+
+    public static final String ISO_CODESYSTEM_URN = "urn:iso:std:iso:";
+    public static final String LANG_CODESYSTEM_URN = "urn:ietf:bcp:47";
+    public static final String MIMETYPES_CODESYSTEM_URN = "urn:ietf:bcp:13";
+
+    public static final String _11073_CODESYSTEM_URN = "urn:iso:std:iso:11073:10101";
+    public static final String DICOM_CODESYSTEM_URL = "http://dicom.nema.org/resources/ontology/DCM";
+
+    public String getNameForSystem(String system) {
+      final int lastPipe = system.lastIndexOf('|');
+      final String systemBaseName = lastPipe == -1 ? system : system.substring(0,lastPipe);
+      final String systemVersion = lastPipe == -1 ? null : system.substring(lastPipe + 1);
+
+      if (systemBaseName.equals(SNOMED_SCT_CODESYSTEM_URL))
+        return getVersionedSystem("snomed", systemVersion);
+      if (systemBaseName.equals(RXNORM_CODESYSTEM_URL))
+        return getVersionedSystem("rxnorm", systemVersion);
+      if (systemBaseName.equals(LOINC_CODESYSTEM_URL))
+        return getVersionedSystem("loinc", systemVersion);
+      if (systemBaseName.equals(UCUM_CODESYSTEM_URL))
+        return getVersionedSystem("ucum", systemVersion);
+      if (systemBaseName.startsWith(HL7_SID_CODESYSTEM_BASE_URL))
+        return getVersionedSystem(normalizeBaseURL(HL7_SID_CODESYSTEM_BASE_URL, systemBaseName), systemVersion);
+      if (systemBaseName.equals(_11073_CODESYSTEM_URN))
+        return getVersionedSystem("11073", systemVersion);
+      if (systemBaseName.startsWith(ISO_CODESYSTEM_URN))
+        return getVersionedSystem("iso"+systemBaseName.substring(ISO_CODESYSTEM_URN.length()).replace(":", ""), systemVersion);
+      if (systemBaseName.startsWith(HL7_TERMINOLOGY_CODESYSTEM_BASE_URL))
+        return getVersionedSystem(normalizeBaseURL(HL7_TERMINOLOGY_CODESYSTEM_BASE_URL, systemBaseName), systemVersion);
+      if (systemBaseName.startsWith(HL7_FHIR_CODESYSTEM_BASE_URL))
+        return getVersionedSystem(normalizeBaseURL(HL7_FHIR_CODESYSTEM_BASE_URL, systemBaseName), systemVersion);
+      if (systemBaseName.equals(LANG_CODESYSTEM_URN))
+        return getVersionedSystem("lang", systemVersion);
+      if (systemBaseName.equals(MIMETYPES_CODESYSTEM_URN))
+        return getVersionedSystem("mimetypes", systemVersion);
+      if (systemBaseName.equals(DICOM_CODESYSTEM_URL))
+        return getVersionedSystem("dicom", systemVersion);
+      return getVersionedSystem(systemBaseName.replace("/", "_").replace(":", "_").replace("?", "X").replace("#", "X"), systemVersion);
+    }
+
+    public String normalizeBaseURL(String baseUrl, String fullUrl) {
+      return fullUrl.substring(baseUrl.length()).replace("/", "");
+    }
+
+    public String getVersionedSystem(String baseSystem, String version) {
+      if (version != null) {
+        return baseSystem + "_" + version;
+      }
+      return baseSystem;
+    }
+  }
+
   public class CacheToken {
     private String name;
     private String key;
     private String request;
     public void setName(String n) {
+      String systemName = getSystemNameKeyGenerator().getNameForSystem(n);
       if (name == null)
-        name = n;
-      else if (!n.equals(name))
+        name = systemName;
+      else if (!systemName.equals(name))
         name = NAME_FOR_NO_SYSTEM;
     }
+
+    public String getName() {
+      return name;
+    }
   }
 
   private class CacheEntry {
@@ -130,7 +202,7 @@ public class TerminologyCache {
   public CacheToken generateValidationToken(ValidationOptions options, Coding code, ValueSet vs) {
     CacheToken ct = new CacheToken();
     if (code.hasSystem())
-      ct.name = getNameForSystem(code.getSystem());
+      ct.name = getSystemNameKeyGenerator().getNameForSystem(code.getSystem());
     else
       ct.name = NAME_FOR_NO_SYSTEM;
     JsonParser json = new JsonParser();
@@ -159,7 +231,7 @@ public class TerminologyCache {
     CacheToken ct = new CacheToken();
     for (Coding c : code.getCoding()) {
       if (c.hasSystem())
-        ct.setName(getNameForSystem(c.getSystem()));
+        ct.setName(c.getSystem());
     }
     JsonParser json = new JsonParser();
     json.setOutputStyle(OutputStyle.PRETTY);
@@ -190,13 +262,13 @@ public class TerminologyCache {
     ValueSet vsc = getVSEssense(vs);
     for (ConceptSetComponent inc : vs.getCompose().getInclude())
       if (inc.hasSystem())
-        ct.setName(getNameForSystem(inc.getSystem()));
+        ct.setName(inc.getSystem());
     for (ConceptSetComponent inc : vs.getCompose().getExclude())
       if (inc.hasSystem())
-        ct.setName(getNameForSystem(inc.getSystem()));
+        ct.setName(inc.getSystem());
     for (ValueSetExpansionContainsComponent inc : vs.getExpansion().getContains())
       if (inc.hasSystem())
-        ct.setName(getNameForSystem(inc.getSystem()));
+        ct.setName(inc.getSystem());
     JsonParser json = new JsonParser();
     json.setOutputStyle(OutputStyle.PRETTY);
     try {
@@ -208,33 +280,7 @@ public class TerminologyCache {
     return ct;
   }
 
-  private String getNameForSystem(String system) {
-    if (system.equals("http://snomed.info/sct"))
-      return "snomed";
-    if (system.equals("http://www.nlm.nih.gov/research/umls/rxnorm"))
-      return "rxnorm";
-    if (system.equals("http://loinc.org"))
-      return "loinc";
-    if (system.equals("http://unitsofmeasure.org"))
-      return "ucum";
-    if (system.startsWith("http://hl7.org/fhir/sid/"))
-      return system.substring(24).replace("/", "");
-    if (system.startsWith("urn:iso:std:iso:"))
-      return "iso"+system.substring(16).replace(":", "");
-    if (system.startsWith("http://terminology.hl7.org/CodeSystem/"))
-      return system.substring(38).replace("/", "");
-    if (system.startsWith("http://hl7.org/fhir/"))
-      return system.substring(20).replace("/", "");
-    if (system.equals("urn:ietf:bcp:47"))
-      return "lang";
-    if (system.equals("urn:ietf:bcp:13"))
-      return "mimetypes";
-    if (system.equals("urn:iso:std:iso:11073:10101"))
-      return "11073";
-    if (system.equals("http://dicom.nema.org/resources/ontology/DCM"))
-      return "dicom";
-    return system.replace("/", "_").replace(":", "_").replace("?", "X").replace("#", "X");
-  }
+
 
   public NamedCache getNamedCache(CacheToken cacheToken) {
     NamedCache nc = caches.get(cacheToken.name);
@@ -520,7 +566,7 @@ public class TerminologyCache {
 
   public void removeCS(String url) {
     synchronized (lock) {
-      String name = getNameForSystem(url);
+      String name = getSystemNameKeyGenerator().getNameForSystem(url);
       if (caches.containsKey(name)) {
         caches.remove(name);
       }
diff --git a/org.hl7.fhir.r4b/src/test/java/org/hl7/fhir/r4b/context/CacheTestUtils.java b/org.hl7.fhir.r4b/src/test/java/org/hl7/fhir/r4b/context/CacheTestUtils.java
new file mode 100644
index 000000000..2fcd71fc7
--- /dev/null
+++ b/org.hl7.fhir.r4b/src/test/java/org/hl7/fhir/r4b/context/CacheTestUtils.java
@@ -0,0 +1,8 @@
+package org.hl7.fhir.r4b.context;
+
+import org.hl7.fhir.utilities.validation.ValidationOptions;
+
+public class CacheTestUtils {
+    public static final ValidationOptions validationOptions =  new ValidationOptions().guessSystem().setVersionFlexible(false);
+
+}
diff --git a/org.hl7.fhir.r4b/src/test/java/org/hl7/fhir/r4b/context/TerminologyCacheTests.java b/org.hl7.fhir.r4b/src/test/java/org/hl7/fhir/r4b/context/TerminologyCacheTests.java
new file mode 100644
index 000000000..1a5222230
--- /dev/null
+++ b/org.hl7.fhir.r4b/src/test/java/org/hl7/fhir/r4b/context/TerminologyCacheTests.java
@@ -0,0 +1,68 @@
+package org.hl7.fhir.r4b.context;
+
+
+import org.hl7.fhir.r4b.model.Coding;
+import org.hl7.fhir.r4b.model.ValueSet;
+import org.hl7.fhir.utilities.tests.ResourceLoaderTests;
+
+import org.junit.jupiter.params.ParameterizedTest;
+
+import org.junit.jupiter.params.provider.CsvSource;
+
+import java.io.IOException;
+
+import java.net.URISyntaxException;
+
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+
+public class TerminologyCacheTests implements ResourceLoaderTests {
+
+
+
+  private TerminologyCache createTerminologyCache() throws IOException {
+    Object lock = new Object();
+    TerminologyCache terminologyCache = new TerminologyCache(lock, null);
+    return terminologyCache;
+  }
+
+
+
+  @ParameterizedTest
+  @CsvSource({
+    "http://terminology.hl7.org/CodeSystem/id,id",
+    "http://hl7.org/fhir/id,id",
+    "http://hl7.org/fhir/sid/id,id",
+    "http://www.nlm.nih.gov/research/umls/rxnorm,rxnorm",
+    "http://snomed.info/sct,snomed",
+    "http://www.nlm.nih.gov/research/umls/rxnorm,rxnorm",
+    "http://loinc.org,loinc",
+    "http://unitsofmeasure.org,ucum",
+    "urn:iso:std:iso:id,isoid",
+    "urn:ietf:bcp:47,lang",
+    "urn:ietf:bcp:13,mimetypes",
+    "urn:iso:std:iso:11073:10101,11073",
+    "my://random/system?with#chars,my___random_systemXwithXchars",
+    "http://dicom.nema.org/resources/ontology/DCM,dicom"
+  })
+  public void testCacheTokenGeneration(String system, String expectedName) throws IOException, URISyntaxException {
+
+    TerminologyCache terminologyCache = createTerminologyCache();
+    ValueSet valueSet = new ValueSet();
+    {
+      Coding coding = new Coding();
+      coding.setSystem(system);
+      TerminologyCache.CacheToken cacheToken = terminologyCache.generateValidationToken(CacheTestUtils.validationOptions,
+        coding, valueSet);
+      assertEquals(expectedName, cacheToken.getName());
+    }
+    {
+      Coding coding = new Coding();
+      coding.setSystem(system + "|dummyVersion");
+      TerminologyCache.CacheToken cacheToken = terminologyCache.generateValidationToken(CacheTestUtils.validationOptions,
+        coding, valueSet);
+      assertEquals(expectedName + "_dummyVersion", cacheToken.getName());
+    }
+  }
+}
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/TerminologyCache.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/TerminologyCache.java
index 287d1cb9b..4ec3c1452 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/TerminologyCache.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/TerminologyCache.java
@@ -38,7 +38,6 @@ import java.io.IOException;
 import java.io.OutputStreamWriter;
 import java.util.*;
 
-import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.Setter;
 import lombok.experimental.Accessors;
@@ -85,6 +84,9 @@ public class TerminologyCache {
   private static final String CAPABILITY_STATEMENT_TITLE = ".capabilityStatement";
   private static final String TERMINOLOGY_CAPABILITIES_TITLE = ".terminologyCapabilities";
 
+
+  private SystemNameKeyGenerator systemNameKeyGenerator = new SystemNameKeyGenerator();
+
   public class CacheToken {
     @Getter
     private String name;
@@ -96,13 +98,79 @@ public class TerminologyCache {
     private boolean hasVersion;
 
     public void setName(String n) {
+      String systemName = getSystemNameKeyGenerator().getNameForSystem(n);
       if (name == null)
-        name = n;
-      else if (!n.equals(name))
+        name = systemName;
+      else if (!systemName.equals(name))
         name = NAME_FOR_NO_SYSTEM;
     }
   }
 
+  protected SystemNameKeyGenerator getSystemNameKeyGenerator() {
+    return systemNameKeyGenerator;
+  }
+  public class SystemNameKeyGenerator {
+    public static final String SNOMED_SCT_CODESYSTEM_URL = "http://snomed.info/sct";
+    public static final String RXNORM_CODESYSTEM_URL = "http://www.nlm.nih.gov/research/umls/rxnorm";
+    public static final String LOINC_CODESYSTEM_URL = "http://loinc.org";
+    public static final String UCUM_CODESYSTEM_URL = "http://unitsofmeasure.org";
+
+    public static final String HL7_TERMINOLOGY_CODESYSTEM_BASE_URL = "http://terminology.hl7.org/CodeSystem/";
+    public static final String HL7_SID_CODESYSTEM_BASE_URL = "http://hl7.org/fhir/sid/";
+    public static final String HL7_FHIR_CODESYSTEM_BASE_URL = "http://hl7.org/fhir/";
+
+    public static final String ISO_CODESYSTEM_URN = "urn:iso:std:iso:";
+    public static final String LANG_CODESYSTEM_URN = "urn:ietf:bcp:47";
+    public static final String MIMETYPES_CODESYSTEM_URN = "urn:ietf:bcp:13";
+
+    public static final String _11073_CODESYSTEM_URN = "urn:iso:std:iso:11073:10101";
+    public static final String DICOM_CODESYSTEM_URL = "http://dicom.nema.org/resources/ontology/DCM";
+
+    public String getNameForSystem(String system) {
+      final int lastPipe = system.lastIndexOf('|');
+      final String systemBaseName = lastPipe == -1 ? system : system.substring(0,lastPipe);
+      final String systemVersion = lastPipe == -1 ? null : system.substring(lastPipe + 1);
+
+      if (systemBaseName.equals(SNOMED_SCT_CODESYSTEM_URL))
+        return getVersionedSystem("snomed", systemVersion);
+      if (systemBaseName.equals(RXNORM_CODESYSTEM_URL))
+        return getVersionedSystem("rxnorm", systemVersion);
+      if (systemBaseName.equals(LOINC_CODESYSTEM_URL))
+        return getVersionedSystem("loinc", systemVersion);
+      if (systemBaseName.equals(UCUM_CODESYSTEM_URL))
+        return getVersionedSystem("ucum", systemVersion);
+      if (systemBaseName.startsWith(HL7_SID_CODESYSTEM_BASE_URL))
+        return getVersionedSystem(normalizeBaseURL(HL7_SID_CODESYSTEM_BASE_URL, systemBaseName), systemVersion);
+      if (systemBaseName.equals(_11073_CODESYSTEM_URN))
+        return getVersionedSystem("11073", systemVersion);
+      if (systemBaseName.startsWith(ISO_CODESYSTEM_URN))
+        return getVersionedSystem("iso"+systemBaseName.substring(ISO_CODESYSTEM_URN.length()).replace(":", ""), systemVersion);
+      if (systemBaseName.startsWith(HL7_TERMINOLOGY_CODESYSTEM_BASE_URL))
+        return getVersionedSystem(normalizeBaseURL(HL7_TERMINOLOGY_CODESYSTEM_BASE_URL, systemBaseName), systemVersion);
+      if (systemBaseName.startsWith(HL7_FHIR_CODESYSTEM_BASE_URL))
+        return getVersionedSystem(normalizeBaseURL(HL7_FHIR_CODESYSTEM_BASE_URL, systemBaseName), systemVersion);
+      if (systemBaseName.equals(LANG_CODESYSTEM_URN))
+        return getVersionedSystem("lang", systemVersion);
+      if (systemBaseName.equals(MIMETYPES_CODESYSTEM_URN))
+        return getVersionedSystem("mimetypes", systemVersion);
+      if (systemBaseName.equals(DICOM_CODESYSTEM_URL))
+        return getVersionedSystem("dicom", systemVersion);
+      return getVersionedSystem(systemBaseName.replace("/", "_").replace(":", "_").replace("?", "X").replace("#", "X"), systemVersion);
+    }
+
+    public String normalizeBaseURL(String baseUrl, String fullUrl) {
+      return fullUrl.substring(baseUrl.length()).replace("/", "");
+    }
+
+    public String getVersionedSystem(String baseSystem, String version) {
+      if (version != null) {
+        return baseSystem + "_" + version;
+      }
+      return baseSystem;
+    }
+  }
+
+
   private class CacheEntry {
     private String request;
     private boolean persistent;
@@ -185,7 +253,7 @@ public class TerminologyCache {
   public CacheToken generateValidationToken(ValidationOptions options, Coding code, ValueSet vs) {
     CacheToken ct = new CacheToken();
     if (code.hasSystem()) {
-      ct.name = getNameForSystem(code.getSystem());
+      ct.setName(code.getSystem());
       ct.hasVersion = code.hasVersion();
     }
     else
@@ -226,7 +294,7 @@ public class TerminologyCache {
     CacheToken ct = new CacheToken();
     for (Coding c : code.getCoding()) {
       if (c.hasSystem()) {
-        ct.setName(getNameForSystem(c.getSystem()));
+        ct.setName(c.getSystem());
         ct.hasVersion = c.hasVersion();
       }
     }
@@ -287,53 +355,31 @@ public class TerminologyCache {
     if (vs != null) {
       for (ConceptSetComponent inc : vs.getCompose().getInclude()) {
         if (inc.hasSystem()) {
-          ct.setName(getNameForSystem(inc.getSystem()));
+          ct.setName(inc.getSystem());
           ct.hasVersion = inc.hasVersion();
         }
       }
       for (ConceptSetComponent inc : vs.getCompose().getExclude()) {
         if (inc.hasSystem()) {
-          ct.setName(getNameForSystem(inc.getSystem()));
+          ct.setName(inc.getSystem());
           ct.hasVersion = inc.hasVersion();
         }
       }
       for (ValueSetExpansionContainsComponent inc : vs.getExpansion().getContains()) {
         if (inc.hasSystem()) {
-          ct.setName(getNameForSystem(inc.getSystem()));
+          ct.setName(inc.getSystem());
           ct.hasVersion = inc.hasVersion();
         }
       }
     }
   }
 
-  private String getNameForSystem(String system) {
-    if (system.equals("http://snomed.info/sct"))
-      return "snomed";
-    if (system.equals("http://www.nlm.nih.gov/research/umls/rxnorm"))
-      return "rxnorm";
-    if (system.equals("http://loinc.org"))
-      return "loinc";
-    if (system.equals("http://unitsofmeasure.org"))
-      return "ucum";
-    if (system.startsWith("http://hl7.org/fhir/sid/"))
-      return system.substring(24).replace("/", "");
-    if (system.startsWith("urn:iso:std:iso:"))
-      return "iso"+system.substring(16).replace(":", "");
-    if (system.startsWith("http://terminology.hl7.org/CodeSystem/"))
-      return system.substring(38).replace("/", "");
-    if (system.startsWith("http://hl7.org/fhir/"))
-      return system.substring(20).replace("/", "");
-    if (system.equals("urn:ietf:bcp:47"))
-      return "lang";
-    if (system.equals("urn:ietf:bcp:13"))
-      return "mimetypes";
-    if (system.equals("urn:iso:std:iso:11073:10101"))
-      return "11073";
-    if (system.equals("http://dicom.nema.org/resources/ontology/DCM"))
-      return "dicom";
-    return system.replace("/", "_").replace(":", "_").replace("?", "X").replace("#", "X");
+  private String normalizeSystemPath(String path) {
+    return path.replace("/", "").replace('|','X');
   }
 
+
+
   public NamedCache getNamedCache(CacheToken cacheToken) {
 
     final String cacheName = cacheToken.name == null ? "null" : cacheToken.name;
@@ -687,7 +733,7 @@ public class TerminologyCache {
 
   public void removeCS(String url) {
     synchronized (lock) {
-      String name = getNameForSystem(url);
+      String name = getSystemNameKeyGenerator().getNameForSystem(url);
       if (caches.containsKey(name)) {
         caches.remove(name);
       }
diff --git a/org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/context/TerminologyCacheTests.java b/org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/context/TerminologyCacheTests.java
index ea46412e5..116eff7e5 100644
--- a/org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/context/TerminologyCacheTests.java
+++ b/org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/context/TerminologyCacheTests.java
@@ -33,6 +33,7 @@ import org.hl7.fhir.utilities.validation.ValidationMessage;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.CsvSource;
 import org.junit.jupiter.params.provider.MethodSource;
 
 import com.google.gson.JsonElement;
@@ -238,6 +239,8 @@ public class TerminologyCacheTests implements ResourceLoaderTests {
     assertTrue(cacheToken.hasVersion());
   }
 
+
+
   @Test
   public void testCodableConceptCacheTokenGeneration() throws IOException, URISyntaxException {
 
@@ -453,4 +456,41 @@ public class TerminologyCacheTests implements ResourceLoaderTests {
 
     assertEquals("http://dummy.org", extracted);
   }
+
+  @ParameterizedTest
+  @CsvSource({
+    "http://terminology.hl7.org/CodeSystem/id,id",
+    "http://hl7.org/fhir/id,id",
+    "http://hl7.org/fhir/sid/id,id",
+    "http://www.nlm.nih.gov/research/umls/rxnorm,rxnorm",
+    "http://snomed.info/sct,snomed",
+    "http://www.nlm.nih.gov/research/umls/rxnorm,rxnorm",
+    "http://loinc.org,loinc",
+    "http://unitsofmeasure.org,ucum",
+    "urn:iso:std:iso:id,isoid",
+    "urn:ietf:bcp:47,lang",
+    "urn:ietf:bcp:13,mimetypes",
+    "urn:iso:std:iso:11073:10101,11073",
+    "my://random/system?with#chars,my___random_systemXwithXchars",
+    "http://dicom.nema.org/resources/ontology/DCM,dicom"
+  })
+  public void testCacheTokenGeneration(String system, String expectedName) throws IOException, URISyntaxException {
+
+    TerminologyCache terminologyCache = createTerminologyCache();
+    ValueSet valueSet = new ValueSet();
+    {
+      Coding coding = new Coding();
+      coding.setSystem(system);
+      TerminologyCache.CacheToken cacheToken = terminologyCache.generateValidationToken(CacheTestUtils.validationOptions,
+        coding, valueSet);
+      assertEquals(expectedName, cacheToken.getName());
+    }
+    {
+      Coding coding = new Coding();
+      coding.setSystem(system + "|dummyVersion");
+      TerminologyCache.CacheToken cacheToken = terminologyCache.generateValidationToken(CacheTestUtils.validationOptions,
+        coding, valueSet);
+      assertEquals(expectedName + "_dummyVersion", cacheToken.getName());
+    }
+  }
 }
diff --git a/org.hl7.fhir.validation/src/test/resources/txCache/org.hl7.fhir.validation/5.0.0/v2-0360_2.7.cache b/org.hl7.fhir.validation/src/test/resources/txCache/org.hl7.fhir.validation/5.0.0/v2-0360_2.7.cache
new file mode 100644
index 000000000..00f2436f5
--- /dev/null
+++ b/org.hl7.fhir.validation/src/test/resources/txCache/org.hl7.fhir.validation/5.0.0/v2-0360_2.7.cache
@@ -0,0 +1,12 @@
+-------------------------------------------------------------------------------------
+{"code" : {
+  "system" : "http://terminology.hl7.org/CodeSystem/v2-0360|2.7",
+  "code" : "BS",
+  "display" : "Bachelor of Science"
+}, "valueSet" :null, "lang":"null", "useServer":"true", "useClient":"true", "guessSystem":"false", "valueSetMode":"ALL_CHECKS", "versionFlexible":"true"}####
+v: {
+  "display" : "Bachelor of Science",
+  "code" : "BS",
+  "system" : "http://terminology.hl7.org/CodeSystem/v2-0360|2.7"
+}
+-------------------------------------------------------------------------------------