It shouldn't come as much of a surprise since Fedora tends to always ship the latest version of the GNU Compiler Collection at release time, but planning is now underway for landing GCC 6 into Fedora 24.

The plan is to have GCC 6 present as the default compiler for Fedora 24. However, due to the timing of releases, it's undecided yet whether all packages would be rebuilt against GCC 6 or just the packages with close ties to the compiler.

GCC 6 feature development is over and GCC 6.1 should be officially released around March or April. Fedora 24 meanwhile is slated to be officially released in mid-May, so it will be a close call. GCC 6 does bring a number of new features and changes.

More details on the GCC 6 planning for Fedora 24 can be found via this Wiki page.