Apple issued the v2.1 software update for the Apple Watch. It mainly contains improved language support and bugfixes. Supported system languages now include several European ones, East Asian ones and Arabic. In addition to that, right-to-left UI mode is now supported. Siri can now understand Arabic (Saudi Arabia and United Arab Emirates). Dictation-only support is added for a number of other languages. For time-keeping, a new complication is available for the Islamic and Hebrew Calendars. Here's the full changelog. Apple Watch OS v2.1 changelog You can read about some additional security improvements here....
Source: http://www.gsmarena.com/apple_watch_gets_v21_update_new_languages_and_bug_fixes-news-15424.php
