From hstore to jsonb (type of column)

Dear all,
from hstore to json, I use this:

ALTER TABLE ONLY mytable
ALTER COLUMN mycolumn
TYPE JSON
USING hstore_to_json(mycolumn)
;

ALTER TABLE ONLY mytable
ALTER COLUMN mycolumn
SET DEFAULT '{}'::json
;

But what would it become for jsonb ?

Replacing json by jsonb does not seem effective since there is no
hstore_to_jsonb fucntion apparently.

Many thanks for your help,

Best regards and many thanks for pgsql ecosystem.

--
Alexandre Delanoë