diff --git a/six/modules/c++/six.sidd/include/six/sidd/DerivedData.h b/six/modules/c++/six.sidd/include/six/sidd/DerivedData.h
index 91dd9a95c..4eee55263 100644
--- a/six/modules/c++/six.sidd/include/six/sidd/DerivedData.h
+++ b/six/modules/c++/six.sidd/include/six/sidd/DerivedData.h
@@ -19,9 +19,9 @@
  * see <http://www.gnu.org/licenses/>.
  *
  */
+#pragma once
 #ifndef SIX_six_sidd_DerivedData_h_INCLUDED_
 #define SIX_six_sidd_DerivedData_h_INCLUDED_
-#pragma once
 
 #include <std/filesystem>
 
@@ -44,8 +44,42 @@
 
 namespace six
 {
+// Emphasize that this is for SIDD 3.0.0
+namespace sidd300
+{
+    // We have to support two ISM versions with SIDD 3.0 :-(
+    enum class ISMVersion
+    {
+        v201609, // the "newer" version; default
+        v13, // the "original" version
+
+        current = v201609
+    };
+    std::string to_string(ISMVersion); // "v201609" or "v13"
+
+    ISMVersion get(ISMVersion defaultIfNotSet); // overloaded on ISMVersion
+    std::optional<ISMVersion> set(ISMVersion); // returns previous value, if any
+    std::optional<ISMVersion> getISMVersion();
+    std::optional<ISMVersion> clearISMVersion(); // returns previous value, if any
+
+    std::vector<std::filesystem::path> find_SIDD_schema_V_files(const std::vector<std::filesystem::path>& schemaPaths);
+}
+    
 namespace sidd
 {
+// six.sidd only currently supports --
+//   SIDD 1.0.0
+//   SIDD 2.0.0
+//   SIDD 3.0.0
+enum class Version
+{
+    v100,
+    v200,
+    v300,
+};
+std::string to_string(Version); // "1.0.0", "2.0.0", "3.0.0"
+Version normalizeVersion(const std::string&);
+
 /*!
  *  \class DerivedData
  *  \brief The implementation of Data for derived products
@@ -54,7 +88,7 @@ namespace sidd
  *  Contains the structs that are the model for SIDD products
  *
  */
-struct DerivedData: public Data
+struct DerivedData : public Data
 {
     /*!
      *  Information related to processor, classification,
@@ -142,6 +176,8 @@ struct DerivedData: public Data
      *  rather than invoking this object directly.
      */
     DerivedData();
+    DerivedData(Version);
+    DerivedData(Version, six::sidd300::ISMVersion); // SIDD 3.0.0 must use this overload
 
     /*!
      *  We are dealing with derived data
@@ -316,15 +352,14 @@ struct DerivedData: public Data
         return std::string(VENDOR_ID);
     }
 
-    virtual std::string getVersion() const
-    {
-        return mVersion;
-    }
+    virtual std::string getVersion() const;
+    virtual void setVersion(const std::string&);
+    void setVersion(const std::string&, six::sidd300::ISMVersion); // SIDD 3.0.0 must use this overload
 
-    virtual void setVersion(const std::string& strVersion)
-    {
-        mVersion = strVersion;
-    }
+    Version getSIDDVersion() const;
+    void setSIDDVersion(Version);
+    void setSIDDVersion(Version, six::sidd300::ISMVersion); // SIDD 3.0.0 must use this overload
+    six::sidd300::ISMVersion getISMVersion() const;
 
     /*
      * Convert the output plane pixel location into meters from the reference
@@ -341,7 +376,9 @@ struct DerivedData: public Data
     bool operator_eq(const DerivedData& rhs) const;
     static const char VENDOR_ID[];
     bool equalTo(const Data& rhs) const override;
-    std::string mVersion;
+
+    Version mVersion = Version::v100; // existing code
+    six::sidd300::ISMVersion mISMVersion = six::sidd300::ISMVersion::current; // only for SIDD 3.0.0
 };
 }
 }
diff --git a/six/modules/c++/six.sidd/include/six/sidd/DerivedXMLControl.h b/six/modules/c++/six.sidd/include/six/sidd/DerivedXMLControl.h
index abc832dee..ae761fafa 100644
--- a/six/modules/c++/six.sidd/include/six/sidd/DerivedXMLControl.h
+++ b/six/modules/c++/six.sidd/include/six/sidd/DerivedXMLControl.h
@@ -19,8 +19,9 @@
  * see <http://www.gnu.org/licenses/>.
  *
  */
-#ifndef __SIX_DERIVED_XML_CONTROL_H__
-#define __SIX_DERIVED_XML_CONTROL_H__
+#pragma once
+#ifndef SIX_six_sidd_DerivedXMLControl_h_INCLUDED_
+#define SIX_six_sidd_DerivedXMLControl_h_INCLUDED_
 
 #include <std/optional>
 #include <std/filesystem>
@@ -28,46 +29,13 @@
 #include <six/XMLControl.h>
 #include <six/Enums.h>
 
+#include <six/sidd/DerivedData.h>
 #include <six/sidd/DerivedXMLParser.h>
 
 namespace six
 {
-
-// Emphasize that this is for SIDD 3.0.0
-namespace sidd300
-{
-    // We have to support two ISM versions with SIDD 3.0 :-(
-    enum class ISMVersion
-    {
-        v201609, // the "newer" version; default
-        v13, // the "original" version
-
-        current = v201609
-    };
-    std::string to_string(ISMVersion); // "v201609" or "v13"
-
-    ISMVersion get(ISMVersion defaultIfNotSet); // overloaded on ISMVersion
-    std::optional<ISMVersion> set(ISMVersion); // returns previous value, if any
-    std::optional<ISMVersion> getISMVersion();
-    std::optional<ISMVersion> clearISMVersion(); // returns previous value, if any
-
-    std::vector<std::filesystem::path> find_SIDD_schema_V_files(const std::vector<std::filesystem::path>& schemaPaths);
-}
-
 namespace sidd
 {
-    // six.sidd only currently supports --
-    //   SIDD 1.0.0
-    //   SIDD 2.0.0
-    //   SIDD 3.0.0
-    enum class Version
-    {
-        v100,
-        v200,
-        v300,
-    };
-    std::string to_string(Version); // "v100", "v200", "v300"
-
 /*!
  *  \class DerivedXMLControl
  *  \brief Turns an DerivedData object into XML and vice versa
@@ -117,5 +85,4 @@ struct DerivedXMLControl : public XMLControl
 }
 }
 
-#endif
-
+#endif // SIX_six_sidd_DerivedXMLControl_h_INCLUDED_
diff --git a/six/modules/c++/six.sidd/include/six/sidd/DerivedXMLParser.h b/six/modules/c++/six.sidd/include/six/sidd/DerivedXMLParser.h
index 6e21d63ec..ffc160e52 100644
--- a/six/modules/c++/six.sidd/include/six/sidd/DerivedXMLParser.h
+++ b/six/modules/c++/six.sidd/include/six/sidd/DerivedXMLParser.h
@@ -19,8 +19,9 @@
  * see <http://www.gnu.org/licenses/>.
  *
  */
-#ifndef __SIX_SIDD_DERIVED_XML_PARSER_H__
-#define __SIX_SIDD_DERIVED_XML_PARSER_H__
+#pragma once
+#ifndef SIX_six_sidd_DerivedXMLParser_h_INCLUDED_
+#define SIX_six_sidd_DerivedXMLParser_h_INCLUDED_
 
 #include <six/XMLControl.h>
 #include <six/sidd/DerivedData.h>
@@ -58,13 +59,13 @@ struct DerivedXMLParser : public six::XMLParser
         XMLElem parent = nullptr) const;
 
 protected:
-    DerivedXMLParser(const std::string& version,
+    DerivedXMLParser(Version,
         std::unique_ptr<six::SICommonXMLParser>&& comParser,
         logging::Logger* log = nullptr, bool ownLog = false);
-    DerivedXMLParser(const std::string& version,
+    DerivedXMLParser(Version,
         std::unique_ptr<six::SICommonXMLParser>&&,
         std::unique_ptr<logging::Logger>&&);
-    DerivedXMLParser(const std::string& version,
+    DerivedXMLParser(Version,
         std::unique_ptr<six::SICommonXMLParser>&&,
         logging::Logger&);
 
@@ -235,10 +236,9 @@ struct DerivedXMLParser : public six::XMLParser
     XMLElem parsePlaneProjection(const xml::lite::Element* projElem, const Measurement& measurement) const;
     XMLElem parseCylindricalProjection(const xml::lite::Element* projElem, const Measurement& measurement) const;
 
-    static
-    std::string versionToURI(const std::string& strVersion)
+    static std::string versionToURI(Version siddVersion)
     {
-        return ("urn:SIDD:" + strVersion);
+        return "urn:SIDD:" + to_string(siddVersion);
     }
 
 private:
@@ -247,4 +247,4 @@ struct DerivedXMLParser : public six::XMLParser
 }
 }
 
-#endif
+#endif // SIX_six_sidd_DerivedXMLParser_h_INCLUDED_
diff --git a/six/modules/c++/six.sidd/include/six/sidd/Utilities.h b/six/modules/c++/six.sidd/include/six/sidd/Utilities.h
index 91b495b48..1bc5713bd 100644
--- a/six/modules/c++/six.sidd/include/six/sidd/Utilities.h
+++ b/six/modules/c++/six.sidd/include/six/sidd/Utilities.h
@@ -19,8 +19,9 @@
  * see <http://www.gnu.org/licenses/>.
  *
  */
-#ifndef __SIX_SIDD_UTILITIES_H__
-#define __SIX_SIDD_UTILITIES_H__
+#pragma once
+#ifndef SIX_six_sidd_Utilities_h_INCLUDED_
+#define SIX_six_sidd_Utilities_h_INCLUDED_
 
 #include <memory>
 #include <vector>
@@ -31,6 +32,7 @@
 #include <types/RgAz.h>
 #include <six/Utilities.h>
 #include <six/sidd/DerivedData.h>
+#include <six/sidd/DerivedXMLControl.h>
 
 namespace six
 {
@@ -82,8 +84,8 @@ class Utilities
      * \return mock DerivedData object
      */
     static std::unique_ptr<DerivedData> createFakeDerivedData();
-    static std::unique_ptr<DerivedData> createFakeDerivedData(const std::string& strVersion);
-
+    static std::unique_ptr<DerivedData> createFakeDerivedData(Version);
+    static std::unique_ptr<DerivedData> createFakeDerivedData(Version, six::sidd300::ISMVersion); // for SIDD 3.0.0
 
     /*
     * Parses the XML in 'xmlStream' and converts it into a DerivedData object.
@@ -156,4 +158,4 @@ class Utilities
 };
 }
 }
-#endif
+#endif // SIX_six_sidd_Utilities_h_INCLUDED_
diff --git a/six/modules/c++/six.sidd/source/DerivedData.cpp b/six/modules/c++/six.sidd/source/DerivedData.cpp
index 8e985035b..9e2930f35 100644
--- a/six/modules/c++/six.sidd/source/DerivedData.cpp
+++ b/six/modules/c++/six.sidd/source/DerivedData.cpp
@@ -30,9 +30,19 @@ namespace sidd
 {
 const char DerivedData::VENDOR_ID[] = "MDA-IS";
 
-DerivedData::DerivedData() :
+DerivedData::DerivedData(Version siddVersion, six::sidd300::ISMVersion ismVersion) :
     productCreation(new ProductCreation),
-    mVersion("1.0.0")
+    mVersion(siddVersion), mISMVersion(ismVersion)
+{
+}
+DerivedData::DerivedData(Version siddVersion) : DerivedData(siddVersion, six::sidd300::get(six::sidd300::ISMVersion::current))
+{
+    if (siddVersion == Version::v300)
+    {
+        throw std::invalid_argument("Must use ISMVersion overload.");
+    }
+}
+DerivedData::DerivedData() : DerivedData(Version::v100) // existing code
 {
 }
 
@@ -89,7 +99,7 @@ DateTime DerivedData::getCollectionStartDateTime() const
 
 const mem::ScopedCopyablePtr<LUT>& DerivedData::getDisplayLUT() const
 {
-    if (mVersion == "1.0.0")
+    if (mVersion == Version::v100)
     {
         if (display->remapInformation.get() == nullptr)
         {
@@ -97,14 +107,12 @@ const mem::ScopedCopyablePtr<LUT>& DerivedData::getDisplayLUT() const
         }
         return display->remapInformation->remapLUT;
     }
-    else if ((mVersion == "2.0.0") || (mVersion == "3.0.0"))
+    else if ((mVersion == Version::v200) || (mVersion == Version::v300))
     {
         return nitfLUT;
     }
-    else
-    {
-        throw except::Exception(Ctxt("Unknown version. Expected 3.0.0, 2.0.0, or 1.0.0"));
-    }
+    
+    throw except::Exception(Ctxt("Unknown version. Expected 3.0.0, 2.0.0, or 1.0.0"));
 }
 void DerivedData::setDisplayLUT(std::unique_ptr<AmplitudeTable>&& pLUT)
 {
@@ -166,5 +174,45 @@ bool DerivedData::equalTo(const Data& rhs) const
     }
     return false;
 }
+
+Version DerivedData::getSIDDVersion() const
+{
+    return mVersion;
+}
+std::string DerivedData::getVersion() const
+{
+    return to_string(getSIDDVersion());
+}
+
+void DerivedData::setSIDDVersion(Version siddVersion, six::sidd300::ISMVersion ismVersion)
+{
+    mVersion = siddVersion;
+    mISMVersion = ismVersion;
+}
+void DerivedData::setSIDDVersion(Version siddVersion)
+{
+    if (siddVersion == Version::v300)
+    {
+        throw std::invalid_argument("Must use ISMVersion overload."); // TODO
+    }
+    setSIDDVersion(siddVersion, six::sidd300::get(six::sidd300::ISMVersion::current));
+}
+
+void DerivedData::setVersion(const std::string& strVersion)
+{
+    // This is an `override` of `six::Data` so there's no way to pass
+    // as six::sidd300::ISMVersion for SIDD 3.0.0.
+    setVersion(strVersion, six::sidd300::get(six::sidd300::ISMVersion::current));
+}
+void DerivedData::setVersion(const std::string& strVersion, six::sidd300::ISMVersion ismVersion)
+{
+    setSIDDVersion(normalizeVersion(strVersion), ismVersion);
+}
+
+six::sidd300::ISMVersion DerivedData::getISMVersion() const
+{
+    return mISMVersion;
+}
+
 }
 }
diff --git a/six/modules/c++/six.sidd/source/DerivedXMLControl.cpp b/six/modules/c++/six.sidd/source/DerivedXMLControl.cpp
index 3c9c0de56..ba3c0e54a 100644
--- a/six/modules/c++/six.sidd/source/DerivedXMLControl.cpp
+++ b/six/modules/c++/six.sidd/source/DerivedXMLControl.cpp
@@ -37,9 +37,7 @@
 #include <six/sidd/DerivedXMLParser200.h>
 #include <six/sidd/DerivedXMLParser300.h>
 
-namespace
-{
-six::sidd::Version normalizeVersion(const std::string& strVersion)
+six::sidd::Version six::sidd::normalizeVersion(const std::string& strVersion)
 {
     std::vector<std::string> versionParts;
     six::XMLControl::splitVersion(strVersion, versionParts);
@@ -84,7 +82,6 @@ six::sidd::Version normalizeVersion(const std::string& strVersion)
 
     throw except::Exception(Ctxt("Unsupported SIDD Version: " + strVersion));
 }
-}
 
 namespace six
 {
@@ -92,11 +89,12 @@ namespace sidd
 {
     std::string to_string(Version siddVersion)
     {
+        // Match "incoming" SIDD version strings; this is also what the XML expects, see normalizeVersion()
         switch (siddVersion)
         {
-        case Version::v100: return "v100";
-        case Version::v200: return "v200";
-        case Version::v300: return "v300";
+        case Version::v100: return "1.0.0";
+        case Version::v200: return "2.0.0";
+        case Version::v300: return "3.0.0";
         default: break;
         }
         throw std::logic_error("Unkown 'Version' value.");
diff --git a/six/modules/c++/six.sidd/source/DerivedXMLParser.cpp b/six/modules/c++/six.sidd/source/DerivedXMLParser.cpp
index 34594a106..4f88c5676 100644
--- a/six/modules/c++/six.sidd/source/DerivedXMLParser.cpp
+++ b/six/modules/c++/six.sidd/source/DerivedXMLParser.cpp
@@ -43,17 +43,14 @@ namespace sidd
 {
 const char DerivedXMLParser::SFA_URI[] = "urn:SFA:1.2.0";
 
-DerivedXMLParser::DerivedXMLParser(const std::string& strVersion,
-    std::unique_ptr<six::SICommonXMLParser>&& comParser,
-    logging::Logger* log, bool ownLog) : XMLParser(versionToURI(strVersion), false, log, ownLog),
+DerivedXMLParser::DerivedXMLParser(Version siddVersion, std::unique_ptr<six::SICommonXMLParser>&& comParser,
+    logging::Logger* log, bool ownLog) : XMLParser(versionToURI(siddVersion), false, log, ownLog),
     mCommon(std::move(comParser)) { }
-DerivedXMLParser::DerivedXMLParser(const std::string& strVersion,
-    std::unique_ptr<six::SICommonXMLParser>&& comParser,
-    std::unique_ptr<logging::Logger>&& log) : XMLParser(versionToURI(strVersion), false, std::move(log)),
+DerivedXMLParser::DerivedXMLParser(Version siddVersion, std::unique_ptr<six::SICommonXMLParser>&& comParser,
+    std::unique_ptr<logging::Logger>&& log) : XMLParser(versionToURI(siddVersion), false, std::move(log)),
     mCommon(std::move(comParser)) { }
-DerivedXMLParser::DerivedXMLParser(const std::string& strVersion,
-    std::unique_ptr<six::SICommonXMLParser>&& comParser,
-    logging::Logger& log) : XMLParser(versionToURI(strVersion), false, log),
+DerivedXMLParser::DerivedXMLParser(Version siddVersion, std::unique_ptr<six::SICommonXMLParser>&& comParser,
+    logging::Logger& log) : XMLParser(versionToURI(siddVersion), false, log),
     mCommon(std::move(comParser)) { }
 
 void DerivedXMLParser::getAttributeList(
diff --git a/six/modules/c++/six.sidd/source/DerivedXMLParser100.cpp b/six/modules/c++/six.sidd/source/DerivedXMLParser100.cpp
index 93d658e89..d9f5e4c6f 100644
--- a/six/modules/c++/six.sidd/source/DerivedXMLParser100.cpp
+++ b/six/modules/c++/six.sidd/source/DerivedXMLParser100.cpp
@@ -34,7 +34,7 @@ namespace six
 {
 namespace sidd
 {
-const char VERSION[] = "1.0.0";
+constexpr Version VERSION = Version::v100;
 const char SI_COMMON_URI[] = "urn:SICommon:0.1";
 const char ISM_URI[] = "urn:us:gov:ic:ism";
 inline static xml::lite::Uri getISMUri()
diff --git a/six/modules/c++/six.sidd/source/DerivedXMLParser200.cpp b/six/modules/c++/six.sidd/source/DerivedXMLParser200.cpp
index de52840aa..9228dabd7 100644
--- a/six/modules/c++/six.sidd/source/DerivedXMLParser200.cpp
+++ b/six/modules/c++/six.sidd/source/DerivedXMLParser200.cpp
@@ -113,7 +113,7 @@ ProjectionType DerivedXMLParser200::getProjectionType(const xml::lite::Element&
 }
 
 
-const char VERSION[] = "2.0.0";
+constexpr Version VERSION = Version::v200;
 const char SI_COMMON_URI[] = "urn:SICommon:1.0";
 inline static xml::lite::Uri getISMUri()
 {
diff --git a/six/modules/c++/six.sidd/source/DerivedXMLParser300.cpp b/six/modules/c++/six.sidd/source/DerivedXMLParser300.cpp
index b5751945c..7392a50d5 100644
--- a/six/modules/c++/six.sidd/source/DerivedXMLParser300.cpp
+++ b/six/modules/c++/six.sidd/source/DerivedXMLParser300.cpp
@@ -39,24 +39,16 @@ namespace six
 {
 namespace sidd
 {
-static const char VERSION[] = "3.0.0";
+constexpr Version VERSION = Version::v300;
 static const char SI_COMMON_URI[] = "urn:SICommon:1.0";
 
 // There is a need to support two different versions of ISM with SIDD 3.0 :-(
-inline static auto getISM_201609_Uri()
-{
-    return xml::lite::Uri("urn:us:gov:ic:ism:201609");
-}
-inline static auto getISM_13_Uri()
-{
-    return xml::lite::Uri("urn:us:gov:ic:ism:13");
-}
 inline static xml::lite::Uri getISMUri(six::sidd300::ISMVersion ismVersion)
 {
     switch (ismVersion)
     {
-    case six::sidd300::ISMVersion::v201609: return getISM_201609_Uri();
-    case six::sidd300::ISMVersion::v13: return getISM_13_Uri();
+    case six::sidd300::ISMVersion::v201609: return xml::lite::Uri("urn:us:gov:ic:ism:201609");
+    case six::sidd300::ISMVersion::v13: return xml::lite::Uri("urn:us:gov:ic:ism:13");
     default: break;
     }
 
diff --git a/six/modules/c++/six.sidd/source/Utilities.cpp b/six/modules/c++/six.sidd/source/Utilities.cpp
index 9698b49bc..fc65f6f64 100644
--- a/six/modules/c++/six.sidd/source/Utilities.cpp
+++ b/six/modules/c++/six.sidd/source/Utilities.cpp
@@ -710,7 +710,20 @@ static void initDED(mem::ScopedCopyablePtr<six::sidd::DigitalElevationData>& ded
     ded->nullValue = -32768;
 }
 
-static void initProductCreation(six::sidd::ProductCreation& productCreation, const std::string& strVersion)
+static int32_t getDESVersion(six::sidd300::ISMVersion ismVersion)
+{
+    if (ismVersion == six::sidd300::ISMVersion::v13)
+    {
+        return 13;
+    }
+    if (ismVersion == six::sidd300::ISMVersion::v201609)
+    {
+        return 201609;
+    }
+    throw std::invalid_argument("Unknown 'ISMVersion' value.");
+}
+
+static void initProductCreation(six::sidd::ProductCreation& productCreation, Version siddVersion, six::sidd300::ISMVersion ismVersion)
 {
     productCreation.productName = "ProductName";
     productCreation.productClass = "Unclassified";
@@ -719,18 +732,18 @@ static void initProductCreation(six::sidd::ProductCreation& productCreation, con
     productCreation.productCreationExtensions.push_back(parameter);
 
     productCreation.classification.securityExtensions.push_back(parameter);
-    if (strVersion != "3.0.0")
+    if (siddVersion != Version::v300)
     {
         productCreation.classification.desVersion = 234; // existing code
     }
     else
     {
-        productCreation.classification.desVersion = 201609; // SIDD 3.0
+        productCreation.classification.desVersion = getDESVersion(ismVersion);        
     }
     productCreation.classification.createDate = six::DateTime();
     productCreation.classification.classification = "U";
 
-    if (strVersion == "1.0.0")
+    if (siddVersion == Version::v100)
     {
         productCreation.classification.compliesWith.push_back("ICD-710");
     }
@@ -934,7 +947,7 @@ static void initGeoData(six::GeoDataBase& geoData)
     geoData.geoInfos.push_back(newGeoInfo);
 }
 
-static void initExploitationFeatures(six::sidd::ExploitationFeatures& exFeatures, const std::string& strVersion)
+static void initExploitationFeatures(six::sidd::ExploitationFeatures& exFeatures, Version siddVersion)
 {
     // The first collection is corresponds to the parent image
     six::sidd::Collection& collection = *exFeatures.collections[0];
@@ -968,7 +981,7 @@ static void initExploitationFeatures(six::sidd::ExploitationFeatures& exFeatures
     polarization->txPolarization = six::PolarizationSequenceType::V;
     polarization->rcvPolarization = six::PolarizationSequenceType::OTHER;
     polarization->rcvPolarizationOffset = 1.37;
-    if (strVersion == "1.0.0")
+    if (siddVersion == Version::v100)
     {
         polarization->processed = six::BooleanType::IS_TRUE;
     }
@@ -986,7 +999,7 @@ static void initExploitationFeatures(six::sidd::ExploitationFeatures& exFeatures
     collection.geometry->extensions.push_back(param);
 
     collection.phenomenology.reset(new six::sidd::Phenomenology());
-    if (strVersion != "3.0.0")
+    if (siddVersion != Version::v300)
     {
         // [-180, 180) before SIDD 3.0
         collection.phenomenology->shadow = six::AngleMagnitude(-1.5, 3.7);
@@ -1008,7 +1021,7 @@ static void initExploitationFeatures(six::sidd::ExploitationFeatures& exFeatures
     exFeatures.product[0].north = 58.332;
     exFeatures.product[0].extensions.push_back(param);
 
-    if (strVersion == "2.0.0")
+    if (siddVersion == Version::v200)
     {
         exFeatures.product[0].ellipticity = 12.0;
         exFeatures.product[0].polarization.resize(1);
@@ -1149,14 +1162,12 @@ static void initProductProcessing(six::sidd::ProductProcessing& processing)
 
 static void populateData(six::sidd::DerivedData& siddData, const std::string& lutType = "Mono")
 {
-    const auto strVersion = siddData.getVersion();
+    const auto siddVersion = siddData.getSIDDVersion();
 
     constexpr bool smallImage = true;
-
-    siddData.setVersion(strVersion);
     const auto elementSize = static_cast<size_t>(lutType == "Mono" ? 2 : 3);
 
-    if ((strVersion == "2.0.0") || (strVersion == "3.0.0"))
+    if ((siddVersion == Version::v200) || (siddVersion == Version::v300))
     {
         // This will naturally get constructed in the course of 1.0.0
         // Separate field in 2.0.0
@@ -1181,7 +1192,7 @@ static void populateData(six::sidd::DerivedData& siddData, const std::string& lu
     //siddData.setImageCorners(makeUpCornersFromDMS());
 
     // Can certainly be init'ed in a function
-    initProductCreation(*siddData.productCreation, strVersion);
+    initProductCreation(*siddData.productCreation, siddVersion, siddData.getISMVersion());
 
     // Or directly if preferred
     siddData.display->decimationMethod = DecimationMethod::BRIGHTEST_PIXEL;
@@ -1238,7 +1249,7 @@ static void populateData(six::sidd::DerivedData& siddData, const std::string& lu
     planeProjection->productPlane.rowUnitVector = six::Vector3(0.0);
     planeProjection->productPlane.colUnitVector = six::Vector3(0.0);
 
-    initExploitationFeatures(*siddData.exploitationFeatures, strVersion);
+    initExploitationFeatures(*siddData.exploitationFeatures, siddVersion);
     initDED(siddData.digitalElevationData);
     initProductProcessing(*siddData.productProcessing);
     initDownstreamReprocessing(*siddData.downstreamReprocessing);
@@ -1307,10 +1318,10 @@ static void update_for_SIDD_300(DerivedData& data) // n.b., much of this was add
     populateData(data);
 }
 
-static std::unique_ptr<DerivedData> createFakeDerivedData_(const std::string& strVersion)
+static std::unique_ptr<DerivedData> createFakeDerivedData_(const Version* pSiddVersion, const six::sidd300::ISMVersion* pISMVersion = nullptr)
 {
     std::unique_ptr<DerivedData> data;
-    if (!strVersion.empty()) // preserve behavior of existing code
+    if (pSiddVersion != nullptr) // preserve behavior of existing code
     {
         //-----------------------------------------------------------
         // Make the object.  You could do this directly, but this way
@@ -1346,11 +1357,18 @@ static std::unique_ptr<DerivedData> createFakeDerivedData_(const std::string& st
         data = std::make_unique<DerivedData>();
     }
 
-    if (!strVersion.empty())
+    if (pSiddVersion != nullptr)
     {
-        data->setVersion(strVersion);
+        if (pISMVersion != nullptr)
+        {
+            data->setSIDDVersion(*pSiddVersion, *pISMVersion);
+        }
+        else
+        {
+            data->setSIDDVersion(*pSiddVersion);
+        }       
     }
-    data->productCreation.reset(new ProductCreation());
+
     data->productCreation->classification.classification = "U";
     data->display.reset(new Display());
     data->geographicAndTarget.reset(new GeographicAndTarget());
@@ -1406,24 +1424,36 @@ static std::unique_ptr<DerivedData> createFakeDerivedData_(const std::string& st
     data->exploitationFeatures->product[0].resolution.row = 0;
     data->exploitationFeatures->product[0].resolution.col = 0;
 
-    if (!strVersion.empty()) // TODO: better check for version; this avoid changing any existing test code
+    if (pSiddVersion != nullptr) // TODO: better check for version; this avoid changing any existing test code
     {
         update_for_SIDD_300(*data);
     }
 
     return data;
 }
-std::unique_ptr<DerivedData> Utilities::createFakeDerivedData(const std::string& strVersion)
+std::unique_ptr<DerivedData> Utilities::createFakeDerivedData(Version siddVersion)
+{
+    if (siddVersion == Version::v300)
+    {
+        throw std::invalid_argument("Must use ISMVersion overload.");
+    }
+    if (siddVersion == Version::v200)
+    {
+        return createFakeDerivedData_(&siddVersion);
+    }
+    throw std::invalid_argument("SIDD version = '" + to_string(siddVersion) + "' is not supported.");
+}
+std::unique_ptr<DerivedData> Utilities::createFakeDerivedData(Version siddVersion, six::sidd300::ISMVersion ismVersion)
 {
-    if ((strVersion == "2.0.0") || (strVersion == "3.0.0"))
+    if (siddVersion != Version::v300)
     {
-        return createFakeDerivedData_(strVersion);
+        return createFakeDerivedData(siddVersion);
     }
-    throw std::invalid_argument("strVersion = '" + strVersion + "' is not supported.");
+    return createFakeDerivedData_(&siddVersion, &ismVersion);
 }
 std::unique_ptr<DerivedData> Utilities::createFakeDerivedData()
 {
-    return std::unique_ptr<DerivedData>(createFakeDerivedData_("").release());
+    return createFakeDerivedData_(nullptr);
 }
 
 }
diff --git a/six/modules/c++/six.sidd/unittests/test_valid_sixsidd.cpp b/six/modules/c++/six.sidd/unittests/test_valid_sixsidd.cpp
index d56fe85fc..036d1d939 100644
--- a/six/modules/c++/six.sidd/unittests/test_valid_sixsidd.cpp
+++ b/six/modules/c++/six.sidd/unittests/test_valid_sixsidd.cpp
@@ -75,9 +75,9 @@ static std::unique_ptr<six::sidd::DerivedData> test_assert_round_trip(const std:
     return six::sidd::Utilities::parseDataFromString(strXML, pSchemaPaths);
 }
 
-inline static const six::UnmodeledS* get_Unmodeled(const six::sidd::DerivedData& derivedData, const std::string& strVersion)
+inline static const six::UnmodeledS* get_Unmodeled(const six::sidd::DerivedData& derivedData, six::sidd::Version siddVersion)
 {
-    if (strVersion != "3.0.0") // Unmodeled added in SIDD 3.0
+    if (siddVersion != six::sidd::Version::v300) // Unmodeled added in SIDD 3.0
     {
         return nullptr;
     }
@@ -87,28 +87,33 @@ inline static const six::UnmodeledS* get_Unmodeled(const six::sidd::DerivedData&
     }
 }
 
-static void test_createFakeDerivedData_(const std::string& testName, const std::string& strVersion, bool validate)
+static void test_createFakeDerivedData_(const std::string& testName, bool validate,
+    six::sidd::Version siddVersion, six::sidd300::ISMVersion ismVersion)
 {
-    const auto pFakeDerivedData = six::sidd::Utilities::createFakeDerivedData(strVersion);
-    auto Unmodeled = get_Unmodeled(*pFakeDerivedData, strVersion);
+    const auto pFakeDerivedData = six::sidd::Utilities::createFakeDerivedData(siddVersion, ismVersion);
+    auto Unmodeled = get_Unmodeled(*pFakeDerivedData, siddVersion);
     TEST_ASSERT_NULL(Unmodeled); // not part of the fake data, only added in SIDD 3.0
 
     const auto schemaPaths = getSchemaPaths();
     const std::vector<std::filesystem::path>* pSchemaPaths = validate ? & schemaPaths: nullptr; // NULL schemaPaths, no validation
 
     auto pDerivedData = test_assert_round_trip(testName, *pFakeDerivedData, pSchemaPaths);
-    Unmodeled = get_Unmodeled(*pDerivedData, strVersion);
+    Unmodeled = get_Unmodeled(*pDerivedData, siddVersion);
     TEST_ASSERT_NULL(Unmodeled);  // not part of the fake data, only added in SIDD 3.0
 }
 TEST_CASE(test_createFakeDerivedData)
 {
-    test_createFakeDerivedData_(testName, "2.0.0", false /*validate*/);
-    test_createFakeDerivedData_(testName, "3.0.0", false /*validate*/);
+    test_createFakeDerivedData_(testName, false /*validate*/, six::sidd::Version::v200, six::sidd300::get(six::sidd300::ISMVersion::current));
+
+    test_createFakeDerivedData_(testName, false /*validate*/, six::sidd::Version::v300, six::sidd300::ISMVersion::v13);
+    test_createFakeDerivedData_(testName, false /*validate*/, six::sidd::Version::v300, six::sidd300::ISMVersion::v201609);
 }
 TEST_CASE(test_createFakeDerivedData_validate)
 {
-    test_createFakeDerivedData_(testName, "2.0.0", true /*validate*/);
-    test_createFakeDerivedData_(testName, "3.0.0", true /*validate*/);
+    test_createFakeDerivedData_(testName, true /*validate*/, six::sidd::Version::v200, six::sidd300::get(six::sidd300::ISMVersion::current));
+
+    test_createFakeDerivedData_(testName, true /*validate*/, six::sidd::Version::v300, six::sidd300::ISMVersion::v13);
+    test_createFakeDerivedData_(testName, true /*validate*/, six::sidd::Version::v300, six::sidd300::ISMVersion::v201609);
 }
 
 static void test_assert_unmodeled_(const std::string& testName, const six::UnmodeledS& Unmodeled)