There are still many things that are unclear about this area since there are no regulations, etc. and don't expect any for quite some time.
I think most commentators (at least the ones I tend to follow) agreed that the exchange of one cryptocurrency for another was a taxable event even before your noted change. It just makes sense and follows the spirit of IRS notice 2014-21. Attached is just one article:
<a rel="nofollow" target="_blank" href="
https://www.thetaxadviser.com/newsletters/2017/apr/cryptocurrency-taxes.html">https://www.thetaxadvi...>
*A reminder that posts in a forum such as this do not constitute tax advice.
Also keep in mind the date of replies, as tax law changes.
