diff --git a/.gitignore b/.gitignore
index c1b854f..bfcd93a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,3 +10,4 @@ SOURCES/nspr-4.34.tar.gz
 /nspr-4.34.tar.gz
 /nspr-4.35.tar.gz
 /nspr-4.36.tar.gz
+/nspr-4.39.tar.gz
diff --git a/nspr.spec b/nspr.spec
index 0d29566..4430fa0 100644
--- a/nspr.spec
+++ b/nspr.spec
@@ -1,4 +1,4 @@
-%global nspr_version 4.36.0
+%global nspr_version 4.39.0
 
 # The upstream omits the trailing ".0", while we need it for
 # consistency with the pkg-config version:
@@ -23,6 +23,7 @@ BuildRequires:  gcc
 # mozilla.org and check out subdirectory mozilla/nsprpub.
 Source0:        %{name}-%{nspr_archive_version}.tar.gz
 Source1:        nspr-config.xml
+Source30:       prwin.h
 
 Patch1:         nspr-config-pc.patch
 Patch2:         nspr-gcc-atomics.patch
@@ -137,6 +138,11 @@ for f in nspr-config; do
    install -c -m 644 ${f}.1 $RPM_BUILD_ROOT%{_mandir}/man1/${f}.1
 done
 
+#cp win.h to old name for compatibility
+cp %{SOURCE30} $RPM_BUILD_ROOT/%{_includedir}/nspr4/prwin.h
+cp $RPM_BUILD_ROOT/%{_includedir}/nspr4/prwin.h \
+   $RPM_BUILD_ROOT/%{_includedir}/nspr4/prwin16.h
+
 %post -p /sbin/ldconfig
 
 %postun -p /sbin/ldconfig
@@ -155,6 +161,9 @@ done
 %{_mandir}/man*/*
 
 %changelog
+* Fri Jun 5 2026 Bob Relyea <rrelyea@redhat.com> - 4.39.0-1
+- Update to NSPR 4.39
+
 * Fri Jul 18 2025 Bob Relyea <rrelyea@redhat.com> - 4.36.0-2
 - Bump version number to clear infrastructure issues
 
diff --git a/prwin.h b/prwin.h
new file mode 100644
index 0000000..5d4eb3d
--- /dev/null
+++ b/prwin.h
@@ -0,0 +1,20 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- 
+*/
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+
+/* This file is deprecated upstream. it's maintained here for source
+ * code compatibility do not expect it in future versions of RHEL */
+
+#ifndef prwin_h___
+#define prwin_h___
+
+/*
+** For platforms other than Win16, define
+** PR_STDIO_INIT() as a No-Op.
+*/
+#define PR_STDIO_INIT()
+
+#endif /* prwin_h___ */
diff --git a/sources b/sources
index 4795a37..aa56777 100644
--- a/sources
+++ b/sources
@@ -1 +1 @@
-SHA512 (nspr-4.36.tar.gz) = 55d21e196508ad29a179639fc8006f44b04dc2c0b5a85895e727f0a4f0ea37aeeceb936e37ac6b271b882a18e9f06d96133a60f19cee6345f8424c1c66e270ee
+SHA512 (nspr-4.39.tar.gz) = 201627666814552e3c98f66a0bdb18194670dcbdbc8cf3241079d918891d46aef1b10e9339beb84802d1de4189993340febab27344e97f8de21ceb1f43c77bda