This app was mentioned in 7 comments, with an average of 1.57 upvotes
update for you: you can win items if you check in at the venue using the ESL app
iphone: https://itunes.apple.com/us/app/esl-event/id1000579069
android: https://play.google.com/store/apps/details?id=com.esl_tech.event
for anyone on Android and rooted, Xposed has a module named Xprivacy that allows you to spoof the lanxess arena location for the ESL app and be eligible for all matches easily.
they fixed the "mock locations" dev option this year, so you need root now.
Link seems to be broken, yes.
This is the app for android
https://play.google.com/store/apps/details?id=com.esl_tech.event
You can get item drops by logging in with your Steam account at our ESL Event app: https://play.google.com/store/apps/details?id=com.esl_tech.event
This only works at the event itself though.