Are there new rules for non-EU citizens from the Balkans who would like to work in the EU?

No. Even though the news might say otherwise, nationals from these countries still need a visa and a work permit for the European Union which they will have to apply for at the respective embassy. This most likely also holds true for 2019.

All information on how to obtain the necessary documents for working in Germany can be found on the websites of the German embassies in these countries. 

In Albania, Kosovo and Serbia, potential migrants also find support at the DIMAK advice centres: https://www.build-your-future.net