diff -up thunderbird-68.2.0/old-configure.in.nss-version thunderbird-68.2.0/old-configure.in
--- thunderbird-68.2.0/old-configure.in.nss-version	2019-10-22 14:50:42.649086398 +0200
+++ thunderbird-68.2.0/old-configure.in	2019-10-22 14:51:11.567171593 +0200
@@ -1537,7 +1537,7 @@ MOZ_ARG_WITH_BOOL(system-nss,
     _USE_SYSTEM_NSS=1 )
 
 if test -n "$_USE_SYSTEM_NSS"; then
-    AM_PATH_NSS(3.44.3, [MOZ_SYSTEM_NSS=1], [AC_MSG_ERROR([you don't have NSS installed or your version is too old])])
+    AM_PATH_NSS(3.44.0, [MOZ_SYSTEM_NSS=1], [AC_MSG_ERROR([you don't have NSS installed or your version is too old])])
 fi
 
 NSS_CFLAGS="$NSS_CFLAGS -I${DIST}/include/nss"