I was not able to test it on Ubuntu because I don't have armhf hardware, but I have just tested it on a Debian porterbox. The only difference between Debian bookworm and sid versions of Qt is presence of this patch.
I used this test code and complied it with qmake && make. mitya57@harris:~/test$ cat test.pro CONFIG += debug warn_all QT = core network SOURCES = test.cpp mitya57@harris:~/test$ cat test.cpp #include <QtCore/QCoreApplication> #include <QtCore/QDebug> #include <QtNetwork/QSslConfiguration> #include <QtNetwork/QSslSocket> int main(int argc, char **argv) { QCoreApplication app(argc, argv); QSslSocket s; QSslConfiguration cfg = s.sslConfiguration(); cfg.setProtocol(QSsl::TlsV1_3OrLater); s.setSslConfiguration(cfg); s.connectToHostEncrypted("www.ubuntu.com", 443); s.waitForConnected(); qDebug() << s.sessionProtocol(); return 0; } Without patch: (bookworm_armhf-dchroot)mitya57@harris:~/test$ ./test -1 With patch: (sid_armhf-dchroot)mitya57@harris:~/test$ ./test 15 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to the bug report. https://bugs.launchpad.net/bugs/1981807 Title: qt5-network openssl3 armhf does not support tls1.3 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qtbase-opensource-src/+bug/1981807/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs