Anyone else who gets the blank store page after updating to IDstore v3.8 will do well to follow the instructions here:
https://www.8theme.com/topic/my-shop-page-under-idstore-is-blank-after-woocommece-2-3-7-update/
After fixing it by making the changes described on the link above, it’s a pretty poor show that the problem gets re-introduced with v3.8 and requires the very same ‘fix’ again! 🙁