diff -rupN PyQt5_gpl-5.13.0/configure.py PyQt5_gpl-5.13.0-new/configure.py
--- PyQt5_gpl-5.13.0/configure.py	2019-07-04 18:44:01.000000000 +0200
+++ PyQt5_gpl-5.13.0-new/configure.py	2019-09-28 01:16:37.793751671 +0200
@@ -2567,10 +2567,6 @@ def generate_sip_module_code(target_conf
     if fatal_warnings:
         argv.append('-f')
 
-    # Make sure any unknown Qt version gets treated as the latest Qt v5.
-    argv.append('-B')
-    argv.append('Qt_6_0_0')
-
     if target_config.prot_is_public:
         argv.append('-P');