diff --git a/include_core/omrutil.h b/include_core/omrutil.h
index 1834838267d..813e8820af0 100644
--- a/include_core/omrutil.h
+++ b/include_core/omrutil.h
@@ -300,7 +300,30 @@ omr_error_t detectVMDirectory(wchar_t *vmDirectory, size_t vmDirectoryLength, wc
 
 uintptr_t getStorageKey(void);
 
-#endif /*if defined(J9ZOS390)*/
+/* ---------------- zosversion.c ---------------- */
+
+#define ZOS_V1R10_RELEASE 20.00
+#define ZOS_V1R10_VERSION 3
+
+#define ZOS_V2R4_RELEASE 27.00
+#define ZOS_V2R4_VERSION 4
+
+/**
+ * Determine if the z/OS version is greater than or equal to a given
+ * release and version. The implementation is based on uname(),
+ * NOT on __osname() as the __osname() release numbers are not
+ * guaranteed to increase.
+ *
+ * For release and version numbers, see
+ * 	https://www.ibm.com/docs/en/zos/2.5.0?topic=functions-uname-display-current-operating-system-name
+ *
+ * @param[in] min_release the release to be checked.
+ * @param[in] min_version the version to be checked.
+ * @return TRUE if the z/OS version is greater than or equal to the given release and version,
+ *			FALSE otherwise.
+ */
+BOOLEAN zos_version_at_least(double min_release, double min_version);
+#endif /* defined(J9ZOS390) */
 
 /**
  * Returns a string representing the type of page indicated by the given pageFlags.
diff --git a/port/unix/omrmmap.c b/port/unix/omrmmap.c
index b5390c4c867..aaf22c79e83 100644
--- a/port/unix/omrmmap.c
+++ b/port/unix/omrmmap.c
@@ -48,6 +48,7 @@
 #include "ut_omrport.h"
 #include "protect_helpers.h"
 #include "omrportpriv.h"
+#include "omrutil.h"
 
 #if defined(J9ZOS390)
 #include "omrvmem.h"
@@ -56,6 +57,10 @@
 #endif /* !defined(MAP_FAILED) */
 #endif /* defined(J9ZOS390) */
 
+#if defined(J9ZOS39064) && !defined(__MAP_64)
+#define __MAP_64 0x10
+#endif /* defined(J9ZOS39064) && !defined(__MAP_64) */
+
 #if defined(AIXPPC)
 #include <sys/shm.h>
 #include <sys/vminfo.h>
@@ -205,11 +210,25 @@ omrmmap_map_file(struct OMRPortLibrary *portLibrary, intptr_t file, uint64_t off
 		spCount++;
 	}
 
-#if defined(J9ZOS39064) && defined(__MAP_64)
+#if defined(J9ZOS39064)
 	if (OMR_ARE_ANY_BITS_SET(flags, OMRPORT_MMAP_FLAG_ZOS_64BIT)) {
-		mmapFlags |= __MAP_64;
+		if (zos_version_at_least(ZOS_V2R4_RELEASE, ZOS_V2R4_VERSION)) {
+			mmapFlags |= __MAP_64;
+		} else {
+			Trc_PRT_mmap_map_file_unix_invalidFlags();
+			errMsg = portLibrary->nls_lookup_message(
+						portLibrary,
+						J9NLS_ERROR | J9NLS_DO_NOT_APPEND_NEWLINE,
+						J9NLS_PORT_MMAP_INVALID_FLAG,
+						NULL);
+			portLibrary->error_set_last_error_with_message(
+						portLibrary,
+						OMRPORT_ERROR_MMAP_MAP_FILE_INVALIDFLAGS,
+						errMsg);
+			return NULL;
+		}
 	}
-#endif /* defined(J9ZOS39064) && defined(__MAP_64) */
+#endif /* defined(J9ZOS39064) */
 
 	if (1 != rwCount) {
 		Trc_PRT_mmap_map_file_unix_invalidFlags();