The default engine's DXMT no longer lets a shared texture kill a game at start.
An Unreal game that creates a shared render target as it starts, ContractVille and the Gold Mining Simulator 2 demo among them, crashed at once on the default engine's DXMT with a CreateTexture2D E_FAIL, while it ran on the Wine 11 engines. The cause was in the Wine underneath: DXMT looks up Wine's D3DKMT adapter by a LUID made from the GPU's IOKit registry ID, which the Wine 10 tree does not assign, so no D3DKMT device ever existed and every shared texture failed. Engine revisions r13 (the default line) and r14 (the GPTK 4 line) carry Highball's own DXMT build, which creates such a texture as a private one when there is no device to share it through, with one line in the log, instead of failing. Everything else in those engines is the same files as before, so only the 19 MB DXMT archive downloads. This build also carries upstream DXMT's work since April, including keyed mutexes and the hooks Steam's overlay needs.
Existing environments stay on their engine until you move them, Settings, Environments, the environment's page, Advanced. The move to r13 keeps the same Wine, so nothing is set up again.