EZConvert can export subtitles compatible with both TTML ver 1. and TTML ver. 2:
The main difference between them is the enhanced functionality implemented in TTML ver. 2 for working with subtitle files in East-Asian languages: TTML ver. 2 adds support for Vertical Subtitles, Ruby and Emphasis (Bouten) characters and horizontal grouping of characters in vertical subtitles.
The exact version of the exported file can be selected from the Compatibility drop-down menu.