Between GCC 4.9 and GCC 5, they made basically the same change Linux made between 2.6.39 and 3.0: they dropped one of the components in the version number. The amount of change between GCC 5, 6, 7, etc. are equivalent to the amount of change between 4.7, 4.8, 4.9, etc.<p>They&#x27;re also using the version 0 in the second component to indicate prereleases. GCC 6.0.0 was the development version of GCC 6. The release candidate was 6.0.1. The first release of GCC 6, which came out today, is 6.1.0. Then there will be development under the name 6.1.1, and the first bugfix release on the GCC 6 line will be 6.2.0. The amount of change between 6.1.0 and 6.2.0 is equivalent to the amount of change between 4.9.0 and 4.9.1 in the old numbering scheme.