20.4 more platforms supported
20.5 Add support for concurrent connections
20.6 Use the RFC6265 test suite
+ 20.7 Support LD_PRELOAD on macOS
21. Next SONAME bump
21.1 http-style HEAD output for FTP
curl with that test suite and detect deviances. Ideally, that would even be
incorporated into our regular test suite.
+20.7 Support LD_PRELOAD on macOS
+
+ LD_RELOAD doesn't work on macOS, but there are tests which require it to run
+ properly. Look into making the preload support in runtests.pl portable such
+ that it uses DYLD_INSERT_LIBRARIES on macOS.
21. Next SONAME bump