It is hard to believe that in the second month of 2015 all the code changes for the 2018 edition of the International Plumbing Code, International Mechanical Code and International Fuel Gas Code have been submitted.
If you missed the deadline, the next possibility of appearing in any of these codes is the 2021 edition. That seems so far off, but that is the nature of the code profession when ICC converted to a single code-change cycle every three years.