I'd like to have Postgis 2.3.5 (or 2.3.4) package with Postgres 10 or earlier, but seems like the available package is only 2.3.3 for now. 2.3.3 doesn't support Postgres 10, therefore, there is no combination of Postgres 10 + 2.3.x.
Seems like Postgis 2.4.2 was shipped before (which was released at the same timing as 2.3.5), but 2.3.5 wasn't included with this update.