Python 2.x is about to die (January 1st, 2020) and IronPython still has not released a version of their 3.x branch.
This topic has been discussed multiple times, but in general, the responses were along the lines of “Just write forward-compatible code”.
However, now that Python 2.x sunsetting is right around the corner (https://python3statement.org), that is no longer a workable solution: oftentimes, the code we use is not just the code we write ourselves, but it is based on third-party dependencies, and those dependencies will drop support for Python 2.x syntax. Some things will simply stop working. So, writing forward-compatible code is not even a choice that we can make.
Is there a strategy on how to move forward? Judging by the activity on open source channels, it would look like using Rhino.Inside from CPython and switching the interpreter from IronPython to a CPython interpreter would be one option.
As a side effect, that would get rid of the gigantic pita that is IronPython and bring us into the extremely active CPython ecosystem (anyone missing numpy? 
).
Cheers