From a historical point of view, in computing, we can testify how character representation has evolved. Since the basic binary encoding of 0s and 1s, each bit has added more expressiveness. Today, Joomla 3.5 is here to introduce the current gold standard, full 4-byte Unicode (Utf8mb4).
Source: The Joomla! Community Magazine™ Issue 2016 April > Administrators, English: Joomla 3.5: from 8-bit ASCII to full Unicode http://magazine.joomla.org/issues/issue-apr-2016/item/3001-joomla-3-5-from-8-bit-ascii-to-full-unicode
