Hi all, Apologies in advance if this isn't the right place for this. A couple of weeks ago, I filed a bug report (https://bugs.launchpad.net/lxml/+bug/1846788) relating to macOS app notarization issues with lxml. As it didn't get a lot of attention, I thought it might be prudent to follow up here. While there are more extensive details in the bug report, the short version is as follows: * Starting in the latest release of macOS (10.15 Catalina), Apple is requiring that apps distributed outside the App Store be submitted to their notarization service. * A number of issues that they're checking are temporarily warnings, but will become errors in January. * Frozen apps that use lxml get the following warning on lxml's etree.cpython-36m-darwin.so: "The binary uses an SDK older than the 10.9 SDK." This will probably become an error in the near future, hampering distribution of these apps. * PySide2 had a similar issue, which was fixed by slightly changing the build flags they used when building wheels. More details are in the full bug report. I'd be happy to work with the maintainers to develop a fix, but wasn't entirely sure where to start. Am I correct that wheel building is controlled by the lxml-wheels repo? If so, would forking it and changing the submodule be a prudent way to run test builds in a CI environment? Additionally, please let me know if I'm totally off-base on some detail of the build system, or if this would be better addressed somewhere else. Thanks in advance. Cheers, Colin