diff -up firefox-45.0.1esr/configure.in.nss firefox-45.0.1esr/configure.in
--- firefox-45.0.1esr/configure.in.nss	2016-04-06 10:20:01.000000000 +0200
+++ firefox-45.0.1esr/configure.in	2016-04-06 10:25:56.998285981 +0200
@@ -53,7 +53,7 @@ dnl ====================================
 MOZJPEG=62
 MOZPNG=10619
 NSPR_VERSION=4
-NSPR_MINVER=4.12
+NSPR_MINVER=4.11
 NSS_VERSION=3
 
 dnl Set the minimum version of toolkit libs used by mozilla
@@ -3451,7 +3451,7 @@ MOZ_ARG_WITH_BOOL(system-nss,
     _USE_SYSTEM_NSS=1 )
 
 if test -n "$_USE_SYSTEM_NSS"; then
-    AM_PATH_NSS(3.21.1, [MOZ_NATIVE_NSS=1], [AC_MSG_ERROR([you don't have NSS installed or your version is too old])])
+    AM_PATH_NSS(3.21.0, [MOZ_NATIVE_NSS=1], [AC_MSG_ERROR([you don't have NSS installed or your version is too old])])
 fi
 
 if test -n "$MOZ_NATIVE_NSS"; then