The Galaxy Tab A 10.1 is yet to be announced by Samsung, but while that glory awaits the 10.1 incher, a firmware has already leaked out, that belonging to its LTE variants actually.
For model no. SM-T580 and SM-T587, the firmwares are available now. You can check our Galaxy Tab A firmware page linked below to download the tablet’s firmware as and when you want.
If you planning to buy one, and intend to root and install custom recovery, then we suggest you already download a firmware and keep it in hand to fix the tablet if any thing goes wrong, ever.