Index: .qmake.conf
===================================================================
diff -u -ra5781739bcbe58c754aff8861561495624bc5b67 -r51e99f2578e0901d9da91a4cb60d1b8858cfe971
--- .qmake.conf	(.../.qmake.conf)	(revision a5781739bcbe58c754aff8861561495624bc5b67)
+++ .qmake.conf	(.../.qmake.conf)	(revision 51e99f2578e0901d9da91a4cb60d1b8858cfe971)
@@ -8,5 +8,5 @@
 BUILD_ROOT = $$shadowed($$PWD)
 
 # individual .pro files can also set these options for standalone builds
-CONFIG += c++20
+CONFIG += c++17
 QMAKE_CXXFLAGS += -Wall -Werror -Wextra