@@ -322,9 +322,12 @@ blockToMarkdown' opts (Div attrs ils) = do
322322 case () of
323323 _ | isEnabled Ext_fenced_divs opts &&
324324 attrs /= nullAttr ->
325− nowrap (literal ":::" <+> classOrAttrsToMarkdown attrs) $$
326− chomp contents $$
327− literal ":::" <> blankline
325+ let attrsToMd = if variant == Commonmark
326+ then attrsToMarkdown
327+ else classOrAttrsToMarkdown
328+ in nowrap (literal ":::" <+> attrsToMd attrs) $$
329+ chomp contents $$
330+ literal ":::" <> blankline
328331 | isEnabled Ext_native_divs opts ||
329332 (isEnabled Ext_raw_html opts &&
330333 (variant == Commonmark ||