You can buy lockboxes right now in Heroes of the Storm, but with the current patch in testing on the game’s test server, you will no longer be able to do so. Random lockboxes are no longer available for Gems on the test server, but can instead be purchased for Gold, making these rewards purely available as an in-game purchase. There’s no changes made to directly purchasing other items, so it’s just the random box of goodies that looks to be changing.
For those who play the game, there are also other relevant changes in the form of a new event featuring Chromie and serious reworks to Lucio, Lunara, and… Chromie again. (She turns up time after time, it seems.) The lockbox change, though, is significant even to those who do not play the title, as it may be indicative of a larger sea change following increased investigation and legislation related to lockboxes. Or it might be more indicative of HotS being currently half-alive in terms of development. There are multiple possibilities.