diff --git a/SPECS-EXTENDED/libdap/libdap-offline.patch b/SPECS-EXTENDED/libdap/libdap-offline.patch
index 1bdadaa312a..2ecf385fb38 100644
--- a/SPECS-EXTENDED/libdap/libdap-offline.patch
+++ b/SPECS-EXTENDED/libdap/libdap-offline.patch
@@ -1,7 +1,8 @@
-diff -up libdap-3.20.3/tests/Makefile.am.orig libdap-3.20.3/tests/Makefile.am
---- libdap-3.20.3/tests/Makefile.am.orig	2019-02-14 10:13:49.000000000 -0700
-+++ libdap-3.20.3/tests/Makefile.am	2019-02-17 15:27:32.426858748 -0700
-@@ -120,7 +120,6 @@ $(EXPRTESTSUITE) $(DMRTESTSUITE) $(GETDA
+diff --git a/tests/Makefile.am b/tests/Makefile.am
+index d325e52..123e73d 100644
+--- a/tests/Makefile.am
++++ b/tests/Makefile.am
+@@ -122,7 +122,6 @@ $(EXPRTESTSUITE) $(DMRTESTSUITE) $(GETDAPTESTSUITE)
  	$(SHELL) '$(DDSTESTSUITE)' $(TESTSUITEFLAGS)
  	$(SHELL) '$(EXPRTESTSUITE)' $(TESTSUITEFLAGS)
  	$(SHELL) '$(DMRTESTSUITE)' $(TESTSUITEFLAGS)
@@ -9,18 +10,19 @@ diff -up libdap-3.20.3/tests/Makefile.am.orig libdap-3.20.3/tests/Makefile.am
  
  # Make sure there are no spaces after the DASTESTSUITE names. jhrg 3/16/15
  # Delete the scripts here and not using CLEANFILES because this target is
-diff -up libdap-3.20.3/unit-tests/Makefile.am.orig libdap-3.20.3/unit-tests/Makefile.am
---- libdap-3.20.3/unit-tests/Makefile.am.orig	2019-02-17 15:27:32.426858748 -0700
-+++ libdap-3.20.3/unit-tests/Makefile.am	2019-02-17 15:28:10.725606175 -0700
-@@ -78,9 +78,9 @@ D4-xml.tar.gz: D4-xml/DMR_*[0-9].xml
+diff --git a/unit-tests/Makefile.am b/unit-tests/Makefile.am
+index 58ecd20..abbf860 100644
+--- a/unit-tests/Makefile.am
++++ b/unit-tests/Makefile.am
+@@ -85,9 +85,9 @@ D4-xml.tar.gz: D4-xml/DMR_*[0-9].xml
  if CPPUNIT
  UNIT_TESTS = marshT arrayT attrTableT structT sequenceT ddsT dasT \
- 	RegexTest ArrayTest AttrTableTest ByteTest MIMEUtilTest ancT DASTest \
+ 	RegexTest ArrayTest GridTest AttrTableTest ByteTest MIMEUtilTest ancT DASTest \
 -	DDSTest	DDXParserTest  generalUtilTest HTTPConnectTest parserUtilTest \
 +	DDSTest	DDXParserTest  generalUtilTest parserUtilTest \
  	RCReaderTest SequenceTest SignalHandlerTest  MarshallerTest \
 -	HTTPCacheTest ServerFunctionsListUnitTest Int8Test Int16Test UInt16Test \
 +	ServerFunctionsListUnitTest Int8Test Int16Test UInt16Test \
  	Int32Test UInt32Test Int64Test UInt64Test Float32Test Float64Test \
- 	D4BaseTypeFactoryTest BaseTypeFactoryTest
+ 	D4BaseTypeFactoryTest BaseTypeFactoryTest util_mitTest
  
diff --git a/SPECS-EXTENDED/libdap/libdap.signatures.json b/SPECS-EXTENDED/libdap/libdap.signatures.json
index 21f3cf201ca..80dcbf0e629 100644
--- a/SPECS-EXTENDED/libdap/libdap.signatures.json
+++ b/SPECS-EXTENDED/libdap/libdap.signatures.json
@@ -1,5 +1,5 @@
 {
  "Signatures": {
-  "libdap-3.20.5.tar.gz": "873c9cabcfb3d0ad48a2c0fcc6701f01234af4e235844a4352c95c8d8562469e"
+  "libdap-3.21.0.27.tar.gz": "0053bd4314a20bca8889b3596c3108cea7dab8849effcf4ec02079fc5d956cc5"
  }
 }
diff --git a/SPECS-EXTENDED/libdap/libdap.spec b/SPECS-EXTENDED/libdap/libdap.spec
index 706d8d8c917..6e99ffb07ff 100644
--- a/SPECS-EXTENDED/libdap/libdap.spec
+++ b/SPECS-EXTENDED/libdap/libdap.spec
@@ -1,17 +1,20 @@
 Name: libdap
 Summary: The C++ DAP2 library from OPeNDAP
-Version: 3.20.5
-Release: 2%{?dist}
+Version: 3.21.0.27
+Release: 1%{?dist}
+
+%global libdap_tag 3.21.0-27
 
 License: LGPLv2+
 Vendor:         Microsoft Corporation
 Distribution:   Azure Linux
 URL: http://www.opendap.org/
-Source0: http://www.opendap.org/pub/source/libdap-%{version}.tar.gz
+Source0:  https://github.com/OPENDAP/libdap4/archive/%{libdap_tag}/%{name}-%{version}.tar.gz
 #Don't run HTTP tests - builders don't have network connections
 Patch0: libdap-offline.patch
 
 BuildRequires: gcc-c++
+BuildRequires: make
 # For autoreconf
 BuildRequires: libtool
 BuildRequires: bison >= 3.0
@@ -25,7 +28,7 @@ BuildRequires: libuuid-devel
 BuildRequires: libxml2-devel
 BuildRequires: openssl-devel
 BuildRequires: pkgconfig
-%ifnarch s390 %{mips}
+%ifarch %{valgrind_arches}
 BuildRequires: valgrind
 %endif
 
@@ -62,7 +65,7 @@ Documentation of the libdap library.
 
 
 %prep
-%autosetup -n %{name}-%{version} -p1
+%autosetup -n libdap4-%{libdap_tag} -p1
 iconv -f latin1 -t utf8 < COPYRIGHT_W3C > COPYRIGHT_W3C.utf8
 touch -r COPYRIGHT_W3C COPYRIGHT_W3C.utf8
 mv COPYRIGHT_W3C.utf8 COPYRIGHT_W3C
@@ -104,10 +107,10 @@ make check || :
 
 %files
 %license COPYRIGHT_W3C COPYING COPYRIGHT_URI
-%doc README NEWS README.dodsrc
+%doc README.md NEWS README.dodsrc
 %{_bindir}/getdap
 %{_bindir}/getdap4
-%{_libdir}/libdap.so.25*
+%{_libdir}/libdap.so.27*
 %{_libdir}/libdapclient.so.6*
 %{_libdir}/libdapserver.so.7*
 %{_mandir}/man1/getdap.1*
@@ -130,6 +133,10 @@ make check || :
 
 
 %changelog
+* Wed Nov 13 2024 Jyoti Kanase <v-jykanase@microsoft.com> - 3.21.0.27-1
+- Update to 3.21.0.27
+- License verified
+
 * Fri Oct 15 2021 Pawel Winogrodzki <pawelwi@microsoft.com> - 3.20.5-2
 - Initial CBL-Mariner import from Fedora 32 (license: MIT).
 
diff --git a/cgmanifest.json b/cgmanifest.json
index 0ed85d46aec..afd44083743 100644
--- a/cgmanifest.json
+++ b/cgmanifest.json
@@ -8941,8 +8941,8 @@
         "type": "other",
         "other": {
           "name": "libdap",
-          "version": "3.20.5",
-          "downloadUrl": "http://www.opendap.org/pub/source/libdap-3.20.5.tar.gz"
+          "version": "3.21.0.27",
+          "downloadUrl": "https://github.com/OPENDAP/libdap4/archive/3.21.0-27/libdap-3.21.0.27.tar.gz"
         }
       }
     },