Yesterday around midnight a patch happened called Dota 2: REBORN.
The dev team of Dota 2 created a whole new UI which looks very slick and modern. Probably League of Legends players coming over to join the Dota Ranks because of that. You can find lots of new threads on reddit right now about how to learn dota when coming from lol.
So here the link to the official blog post of dota2 for the new beta. Just activate it with a right-click on Dota 2 in your Steam Game Library and select Properties. Then go to the DLC Tab and check the Dota 2 – Reborn Beta to have a checkmark in the box. Click ok and it should download the update.
BTW – don’t pause the update or it’s going to restart from the beginning!