diff --git a/http/ut/utility_test.cpp b/http/ut/utility_test.cpp
index 191a16a..fc8b90e 100644
--- a/http/ut/utility_test.cpp
+++ b/http/ut/utility_test.cpp
@@ -56,3 +56,22 @@
     EXPECT_TRUE(crow::utility::base64Decode(encoded, decoded));
     EXPECT_EQ(data, decoded);
 }
+
+TEST(Utility, GetDateTime)
+{
+    // some time before the epoch
+    EXPECT_EQ(crow::utility::getDateTimeStdtime(std::time_t{-1234567}),
+              "1969-12-17T17:03:53Z");
+    // epoch
+    EXPECT_EQ(crow::utility::getDateTimeStdtime(std::time_t{0}),
+              "1970-01-01T00:00:00Z");
+    // some time in the past after the epoch
+    EXPECT_EQ(crow::utility::getDateTimeUint(uint64_t{1638312095}),
+              "2021-11-30T22:41:35Z");
+    // some time in the future, beyond 2038
+    EXPECT_EQ(crow::utility::getDateTimeUint(uint64_t{41638312095}),
+              "3289-06-18T21:48:15Z");
+    // the maximum time we support
+    EXPECT_EQ(crow::utility::getDateTimeUint(uint64_t{253402300799}),
+              "9999-12-31T23:59:59Z");
+}
diff --git a/http/utility.hpp b/http/utility.hpp
index 6f81be8..d141056 100644
--- a/http/utility.hpp
+++ b/http/utility.hpp
@@ -1,9 +1,10 @@
 #pragma once
-
 #include "nlohmann/json.hpp"
 
 #include <openssl/crypto.h>
 
+#include <boost/date_time/posix_time/posix_time.hpp>
+
 #include <chrono>
 #include <cstdint>
 #include <cstring>
@@ -572,26 +573,28 @@
 }
 
 /**
- * Method returns Date Time information according to requested format
+ * Method returns Date Time information in the ISO extended format
  *
- * @param[in] time time in second since the Epoch
+ * @param[in] timestamp in second since the Epoch; it can be negative
  *
- * @return Date Time according to requested format
+ * @return Date Time in the ISO extended format
  */
-inline std::string getDateTime(const std::time_t& time)
+inline std::string getDateTime(boost::posix_time::seconds secondsSinceEpoch)
 {
-    std::array<char, 128> dateTime;
-    std::string redfishDateTime("0000-00-00T00:00:00Z00:00");
+    boost::posix_time::ptime epoch(boost::gregorian::date(1970, 1, 1));
+    boost::posix_time::ptime time = epoch + secondsSinceEpoch;
+    // append zero offset to the end according to the Redfish spec for Date-Time
+    return boost::posix_time::to_iso_extended_string(time) + 'Z';
+}
 
-    if (std::strftime(dateTime.begin(), dateTime.size(), "%FT%T%z",
-                      std::localtime(&time)))
-    {
-        // insert the colon required by the ISO 8601 standard
-        redfishDateTime = std::string(dateTime.data());
-        redfishDateTime.insert(redfishDateTime.end() - 2, ':');
-    }
+inline std::string getDateTimeUint(uint64_t secondsSinceEpoch)
+{
+    return getDateTime(boost::posix_time::seconds(secondsSinceEpoch));
+}
 
-    return redfishDateTime;
+inline std::string getDateTimeStdtime(std::time_t secondsSinceEpoch)
+{
+    return getDateTime(boost::posix_time::seconds(secondsSinceEpoch));
 }
 
 /**
@@ -606,7 +609,7 @@
 inline std::pair<std::string, std::string> getDateTimeOffsetNow()
 {
     std::time_t time = std::time(nullptr);
-    std::string dateTime = getDateTime(time);
+    std::string dateTime = getDateTimeStdtime(time);
 
     /* extract the local Time Offset value from the
      * recevied dateTime string.