Just wanted to mention the info that the biggest or second biggest (depends on how you count, it's a duopoly) cable ISP in Serbia is finishing up the migration to DOCSIS 3.1, and will provide gigabit speeds to cable customers. However, the upload will still be 50 Mbps maximum. Currently the fastest they have is 300/15 Mbps, which is better than what they will offer with DOCSIS 3.1 -- 1000/50 Mbps.
Most of their passive and active equipment in areas which have been fully "digitalized" is 3.1 compliant, they just need to finish the whole city and then they will start marketing the offer. Modems will have to be changed as well as equipment on the customer's side which they haven't done yet, so it will take quite some time.
They "promised" it by the end of 2019. (in 2016.), seems it will be 2025. By that time the Chinese government and Telekom Srbija will have FTTH to every home.