Complex sentence: The foundation's precursor, the Lotte Lehmann League, published a newsletter from 1989 to 1994; the League has since 2011 been re-established via a website.
Split into simpler sentences: The foundation's precursor, the Lotte Lehmann League, published a newsletter from 1989 to 1994. The League has since 2011 been re-established, with only a website.