This release enables you to query inside the polygon on the sphere using the Postgresql Polygon type.
I.e before you had to do
select * from tab where q3c_poly_query(ra,dec, ARRAY[0,0,0,1,1,1,1,0]);
But now you can use the native polygon type
select * from tab where q3c_poly_query(ra,dec, '((0,0),(0,1),(1,1),(1,0))'::polygon);
to use the new release, after the installation you HAVE to execute
alter extension q3c update to '1.8.0';
If you are using a version older than 1.7.0 you may have to first update to 1.7.0 then to 1.8.0