Not all digital copies are created equal. To ensure you have version 1.1.641, you should look to these storefronts:
To understand 1.1.641, we need the timeline:
Yes—but with nuance. Recently, the SC4 community released a (Project Phoenix), but it is experimental. For 99% of players, 1.1.641 is still the safest, most compatible, and most documented version.