I've tried googling this, and I'm having an unusually hard time finding out the maximum capabilities of different versions of displayport.
Displayport 1.2 offers twice the bandwidth. Both support 4K at 60hz.
However, 144hz at 1440p requires much greater bandwidth than 4K at 60hz. So I'm wondering if displayport 1.0 can even handle the 144Hz.
144Hz at 1440p requires about the same amount of bandwidth as 4K 60Hz. 12Gbps for 4K@60 vs 12.7Gbps for 1440@144. DisplayPort 1.2 can carry up to 17.28Gbps, ~4K 75Hz. DisplayPort 1.1 maxes out at half that, and is not capable of 2560x1440 at 144Hz.
But there are no 2560x1440 144Hz monitors with DisplayPort 1.1 or below anyway for that exact reason, and the last graphics cards with DP 1.1 were the GeForce 500 series cards, so it's a bit of a moot point, you won't be dealing with a DisplayPort connection below 1.2 with any newer hardware. And if you're just shopping for cables, be aware that DisplayPort cables do not have revisions. There is only one type of DisplayPort cable.